How to service an outboard motor

Hey there, Dangarstu here. Today’s video
is in on doing a general services of an outboard It’s something I probably should have done
a long time ago. We’re got a lot of videos on
various tasks you might do if you got a fault or something you want to service individually
but this time I just go through the whole list of things I would do an outboard to come to
the shop and things you can all do yourself if you’re looking at servicing your
boat before the start of the boating season. Now the outboard I’ve got here at the moment
is a two-stroke so I will find an old four stroke
somewhere just to to go through changing the sump oil
if you happen to have a four stroke, but everything else is pretty much the same so I’ll use
this, it’s a Yamaha 30 we’re going to be looking at,
so I’ll use this as our main outboard for this and I’ll just show you where there are some differences.
Now one of the first things I’ll do with this service is a kind of general sort of visual
inspection it’s very easy to sort of dive straight into changing oil and doing
all this sort of stuff, but when you service
an outboard is it really good opportunity to cast your
eye over it in a way you wouldn’t normally
when you’re just out boating so I’ll grab the camera we’ll just have a look around
and I’ll show you the sort of things we’re looking for So starting here one of the first things that just
caught my eye then is how much this fuel hose is
is starting to perish. Certainly the outer casing anyway. depending on how this is going, you can see this
whole hose is pretty bad so I’d say that’s pretty much in line for replacement If it’s just the end you can cut a bit off and
put your hose clamp a bit further but I’d say that’s getting close to the end of its life.
This boat lives outdoors so it cops a lot of UV. Now, something else I just noticed just looking around,
and we’ll be doing this later, is that a lot of this grease here is quite hard. That’s not one of the things
I would particularly be looking for as part of a visual inspectioni, but it’s just one of the
other things that first caught my eye. So when we go to put new grease in
this we might have a bit of trouble trying to push the old grease out given how hard it has
become, but we’ll cross that bridge when we come to it. Now, the other thing you’re really looking for is
loose bolts and things. connections, electrical connections can be quite
frustrating diagnose if they get an intermittent poor connection which can quite often
be from things vibrating breaking loose
so looking for any nuts and things that have
vibrated loose and don’t look up to scratch even just putting a socket on them
giving a really sort of a turn, you’re not looking to crank them to the point of
snapping them or anything but it is a good way to feel whether they’ve come loose,
and of particular importance with outboards obviously is whether this, and see I can even see there
this mounting bolt is completely loose so that’s the kind of thing you looking for.
If you just jump into doing, you know, your oil change, your spark plug change,
these are the sorts of things you’ll
miss so just give it all a once over have a look at everything. Then we’ve got
things like the annode under here. not too bad, it’s got a fair bit of meat left on it
So all your bolts, your linkages, your electrical connections So, all this stuff doesn’t
happen any particular order but one of things I tend to look at first is things like the
fuel filters. I’m looking at cleaning it but I’m also just having a look what’s
in it. You know, if it’s got some water in it then you might need to do a carburettor clean.
If it’s got a lot of junk in it we might
look at flashing the tank out So I consider this outboard service to
be pretty much from the fuel tank itself to the outboard, but I would highly recommend you
look at the whole boat, the steering, the lights, the bilge pump etc, etc,
but in this case we are going to limit
to the motor itself. So these will have a little 14mm socket on
the bottom, so I’m just going to grab a little
spanner and we’ll wind this fuel filter off. So when this bowl comes off There is the bowl itself and then this little mesh filter.
The mesh filter will quite often stick up into this top section It’s seals up against there.
So, we’ve got the bowl here, and the little mesh
filter that’s just pressed in.
The filter itself doesn’t look too bad, a few bits of dirt So if we look in here, you’ll see there is a bit of rubbish
floating around in there. Hopefully that’s focusing.
Not too bad do be honest, it’s there to do a job So I’ll just tip that rubbish out of here so that’s
gone, I’ll spray this mess with a bit of break cleaner
or something You could use a bit of compressed air but just be
careful, it’s a bit delicate that’s all
So I’ll pop this back together now There’s an o-ring in the top that seals here
just have a check the condition of that because you don’t want fuel leaking out from
this fuel filter. So, just press that back on screw the fuel filter on
So I’m just going to give this a tiny 16th of a turn
just to secure it. Lots of different outboards will have
multiple fuel filters, particularly things like EFI models. They’re have a course filter,
a fine filter. You might have a larger water seperating filter
on the inside of the transom, so
just make sure you go through all the fuel filters that the motor has. You can see
the spark plugs are pretty rusty. External rust like this doesn’t necessarily mean
the plugs aren’t working that well but I’d say they are definitely due for replacement so
we’ll pop those out and have a look at
the electrodes on them and then we’ll pop some new ones in.
I’m going to get these out using one of
these spark plug tools. This is a 13/16ths. Any deep socket will do but you do get
special spark plug sockets which can make
life a little easier just for holding the plug.
So this is a fair bit of carbon, it looks like
it has been running quite rich which is interesting. When you take your plugs out,
keep them in order as it good to know which
plug went with which cylinder. If one plug looks particularly bad it can
be an indication that there is a problem
with that cylinder, well, generally is, and if you take them all out and mix them
then you won’t know which cylinder it was.
So once again, pretty similar so no big difference between the two which is another good thing.
The owner did tell me this outboard was running on about double the oil it was supposed to be
so that can explain a bit of that fouling of the plugs Now I’ve got those out I’m going to do a
compression test on this just a bit of a health check but also to record against
services so that you can track the compression as the years go by. At the start of each
season you can know what you compression was last year
what it is this year, is there any obvious deteriation,
particularly in one cylinder. if it’s deteriorating evenly that’s just the
outboard getting older. If one cylinder drops,
maybe you’ve got something you need to look at. I’ve got a video on compression testing
so I’m not going to go through it in huge detail
but just showing the steps I’ll take. I’ve got that in cylinder one so I’ll just go and
crank it over a few times with the throttle open. So that’s come out at 125. That’s pretty good
for an outboard of this vintage.
So I’ll just reset that and do the bottom cylinder.
The best I could get out of that after even more
pulling was 60, so this engine’s not healthy. The owner told me this outboard wasn’t healthy
so what I’m going to do is swap it as they’ve
given me another outboard to put on this
then we’ll continue the service on the new outboard. No point now putting any time or money into this one
until it gets fixed. So, I’ll leave this one as it is, do a quick
swap and then we’ll pick up. So I guess that’s one way you can service an
outboard. Take a look around and if you see
anything wrong, put a new motor on.
So lets push on with this one.
That one I’m going to take the head off
at some stage and have a look. To give you
more of the history the owner had
reported that all of a sudden it had been
harder to pull start it than it was before,
so I think one of the rings is caught up in
the cylinder making it hard to turn over,
giving us this compression problem, and
that’s why this boat came in with a second
motor in it, expecting the other one wouldn’t
really be servicable.
As you can see this outboard is much cleaner
that the other one. It doesn’t look like it’s
done anywhere near as much work.
Plugs weren’t as rusty, you’ve obviously got
the oil you get from a two stroke motor, but
they’re not quite as fouled up as the ones from
the original outboard either, but the fuel
filter has got quite a bit of residue in it,
same with the mesh. The fuel smells terrible,
it’s really gone off.
So I think this outboard hasn’t done a lot
of work, but it probably sat around for a long time. So I’ll pop some new plugs in while we’re here
before we push on. Obviously, take a look at the
plugs that are in it, they are 99% likey to be
the right ones unless someone else has been at it. The service
manual will tell you and it’s also really common for outboards have a little
sticker telling you. In this case it’s NGKB8HS10, so I’ll go grab a couple of those
and we’ll go pop them in. So one thing worth
noting you’ll see on the package here hopefully it’s focusing, so the ten
in the BHS1010 indicates a one millimetre gap
They come pre-gapped so there is
no real issue there. Once it’s threaded in and it’s snugged,
you need to turn it about and extra
half to two-thirds of a turn when it’s new to get the crush washer to seat properly. so there’s no torque setting for these
spark plugs. Just seat it down and then turn it an extra half to two-thirds of a turn. So I’m
just going to gently wind these in by
hand to make sure they’re not cross threaded you can really feel it
when you’re just using your fingers. You can even start by winding it a little bit
counter-clockwise until you
feel it sort of click as the thread engages then start winding it clockwise. And once
it’s there, snug, turn it that extra half turn.
Make sure you’re leads go back on in the same order. Often you can’t get them out of order because
the top lead won’t reach the bottom, but just be careful if they are
long enough to reach and make sure that pushed on properly and not just resting on otherwise you’ll get an intermittent spark
out of them.
So that’s spark plugs, pretty straight forware Nice easy job you can do yourself,
that’s for sure
Next thing I’m going to do is drain the gearbox oil.
Those of you who subscribe to the channel will have
seen this a few times in the past so I won’t
agonise over this.
Now this drain plug’s pretty tight
So I’m just going to grab a shifter and put it on
the end of the screwdriver. Quite often you’ll need
to do this if these have been done up too hard.
So I’m just going to use one hand to hold the
screwdriver in and the other hand to bring the
shifter around until it’s cracked. You’ll see here this has got a few
metal filings on it. This bottom plug has a magnet
in it. It’s designed so that any little bits of
metal that come off the gears are designed to
get attached to this magnet rather than just
floating around in the gearbox.
Also going to now undo this top screw which
will let the air in and let the oil flow out more
freely. I’ll bring the camera in and show you.
This oil is in really good nick. There’s no
problem with that. If it looked a bit milky
the oil seals would be gone, at least one of them,
but in this case it’s all looking pretty healthy.
So I’m just going to let that drain and then do
a quick pressure test just to confirm there aren’t
any leaks in this gearbox. Because it has been
sitting on dry land, the oil seals may have
perished but no water has got in, so the pressure
test really is the definitive way to know. This outboard didn’t have a prop on it so
I’m going to swap the prop from the other one,
but as a general part of a service I would
highly recommend taking the prop off and
just taking a look if there is any fishing line
in here behind the thrust washer because if
you have picked up any fishing line, that’s
what’s going to cut this seal and eventually get water into your gearbox
oil. So, I’m also now just going to clean this spline and put a bit of grease on it.
Give it a bit of a wipe with a rag. Then
just a bit of marine grease. I’m going to
pump this from a grease gun. That’s all
good to go now, ready to put the prop
back on. I’ll show you putting it on, and
taking it off is pretty much just the same
process in reverse.
To do the pressure test on the gearbox now
that’s it’s finished draining, I’m just going
to put this top plug back in. Do that up
snugly. Then this is just a threaded barb to suit this
gearbox attaching a bit of hose to this
pressure gauge pump. I’ve got a video
on doing this particular test and making
a cheap version of this tool so if you’re
interested check that one out, I’ll put a
link to it. Then all I’m going to do is pump
it up. So we’ve now got 10 PSI, and the spec
is that the gearbox should be able to hold
10 PSI for, I think it’s only like 10 seconds
or something, not a long period of time. So this gearbox is holding pressure and we
can pretty much give it a clean bill of health.
Now we know that the oil seals are good, we’ll
pop some fresh oil in.
If that pressure was dropping, we can have a
listen around and hear where that air is escaping.
One of three places. It’s either the oil seals
around the prop shaft oil seals around the drive
shaft or oil seals aroung the gear selector. The
drive shaft and gear selector linkage you need the
leg off to see. Both these plugs have these red fibre washers on
them so I’m just going to grab a couple of new washers.
Yamaha sell these washers as a set of two as a
part of a service kit, so they’re pretty easy to
Now what I’ve got, this is actually a bottle of
Yamaha gearcase lube. It’s essentially a kind of
75/ 80 weight oil, I just keep using this bottle
because it’s a convenient way get it in. It’s
actually got some Liqui Moly gearcase oil in it
which is good oil, but as long as it’s the right
stuff, but what I like about that bottle is that
it is a nice convenient pump pack that once again
has the right thread. Now I’ve got this little pump pack threaded into
the bottom hole, nothing in the top hole, I’ll
start pumping this oil through until we get
oil coming out the oil level hole. The initial
oil that comes through might be a bit aerated,
so give it a chance for the bubbles to rise up
out of the oil and then give it a few more pumps
until you get pretty clean solid oil coming out
that top hole.
So here we go, once it starts coming out you’ll
see how there’s just a few little bubbles in
the oil, so I’m just going to let that sit for
a little bit, the bubbles will rise up out of
the oil in the gearbox. Give it a few more pumps and we’re getting reasonably
clear oil out now. So the next thing I’m going to
do is put that top plug in because the lack of air coming out will
help me undo this bottom one without it all rushing out. So we’ll put the top one
in and then the bottom one in.
So once it’s snug, I’ve used that shifter
again to give it an 8th of a turn, or less
even, not enough to make it impossible to get
undone again, but enough to make sure water
doesn’t get past that new fibre washer. Same with the bottom plug, just up snug and then
another 8th of a turn. All right, gearbox oil
done. Next up I’m just going to run around
with the grease gun and put some grease in all
the grease nipples. So I’ll show you where they
are and what they are about.
So they’re a little bit different on each outboard.
We’ve got one down here and this is the pivot
tube coming down through here, there’s one
here which I think is just to grease this locking
pin and then there’s one around here and
here for the tilt tube. Now this tilt tube
is a solid tube, so none of this grease gets
into the tilt tube, if you have a push-pull steering cable, this
is purely for the motor tilting up and down, nothing to do with your steering.
Just be aware of that seems to be a bit of a common misconception. So as I pump in grease it’s actually filling
the cavity between this casing and the pivot tube inside,
and also going in behind the nylon bushings.
So you’ll see here as you pump, grease is
coming out the side here. once you get clean grease, you’ll know
you’ve displaced all the old grease that you can it’s very messy doing this but it’s
all this old grease coming out that
you are trying to get, that’s sort of your goal. In this case we were putting in the bottom
and it was coming out the top which is kinda good
it means making all the way up but it’s nice to see grease
coming out the bottom bushing and the top if it doesn’t it means that
the grease has gone a bit hard and it’s sort of finding this path of least
resistance, this grease has found a way out and it’s all going to come out there. By
doing this job regularly you will display that old grease with
new grease before it gets a chance to go hard which means it is going to spread more evenly
so this is something I recommend doing quite regularly. In addition to the
grease nipples on the pivot tube and tilt tube etc a lot of these linkages have a little bit of
grease on them. Now, it’s kinda good to see this outboard really because it is in quite new condition
and from the factory there isn’t a lot of grease everywhere and I do find that a
lot of these outboards to tend to get over greased. I think it’s a bit of a double-edged sword yes some areas can run smoothly like for
example here you can see where these mechanisms run over a cam style arrangement.
A little bit of grease on their can make it smoother but grease can also collect a lot of
dirt so if you do start greasing linkages, which is definitely part of the
service process make sure you do so reasonably sparingly you know it’s usually just a small dab,
you know, wiping these types of surfaces any of these sort of linkages, these ball joints
can be lubricated but I guess just do it it with a less is more sort
of attitude is all I’m trying to say. So just have a look around here. All our linkages
are on this starboard side. Just got this fuel filter
I’ll attach again. So really if you are going to do this lubricating it’s things like these cams
these little sort of nylon bushings and these pin sort of
joints for things like chokes, throttles
gear selectors etc. The grease I use for that if you’re interested
is this a tube of this Yamaha grease “A”. you can buy it at most Yamaha dealers and will last you forever and a day,
you don’t use a lot of this grease at all,
you use it very sparingly. Not that any other marine grease isn’t
going to be fine. Most marine grease is seems to be some sort
of Lithium-based grease, I just picked this up
because it is also a nice handy little tube
compared to those guns or a tub of grease.
I’ll swap this prop onto the other outboard now but this procedure is essentially the same as
if you were taking the prop off,
checking for fishing line and putting it back,
greasing it. So, this split pin has just been bent down here
so all we need to do is get these two tail,
00:23:22,469 –>00:23:26,859
the tails of the split pin straight again,
or roughly straight. And then just get a pair of side cutters in
to get a grip on it wiggle and lever it out Then once that’s out, we’ll just put a socket
on here. This nuts a 22 mm socket on this
outboard. Then I’m just going to put a block
of wood in here to stop the prop rotating and grab that nut off. So nut, washer, prop.
When installing this prop, first thing on
is the thrust washer, then the prop itself,
the spacer, not all outboards have spacers
there, flat washer then this castlated nut.
Same as taking it off, just use the bit of
wood to block it. Then we’re just going to
tighten this until it’s snug and then I’m going
to wind it just a smidge on, and I’ll show you
in here. So this is where the hole in the prop
shaft is here and we’re just making sure this is lined up with the little butresses on this
castleated nut. So I’ll go grab a new split
pin and we’ll lock this off. So I’ll just slip this down here.
Sometimes it can be a little bit tricky
because the pin you’ve got is longer than the space here in the outboard you might
have to bend it slightly to get in or just trim the ends before you push it in
A few taps gets it in. The shorter leg I’m just going to bend up
and over the nut, and the bottom leg
I’m just going to trim off, and that’s
good to go.
We’ll look at the water pump on this
outboard next. Now, the water pump’s
a funny thing. They can run for a long time,
it is a little bit of effort to check them
out and it does depend on how much running
the motor gets, but at the same time it’s
kinda critical. I’d be inclined to take a
look every couple of years at the longest,
so maybe every second season or something like
that, but just be aware that if you do take
it apart, depending on the style of water pump,
you will potentially need some sort of gasket
or whatever to replace it. Now, I’ve got a
full water pump service kit for this so I’ll
show you what comes in that. I’m not expecting
to need to use much of this for this particular
outboard because this is the new one we’ve put
on, so I’ll probably end up putting most of these
parts onto the one we took off at the start
of the video, but it’s always good to have
these parts on hand.
This Yamaha kit’s pretty complete, possibly a
little bit of overkill for a service. You even get a nice picking list of what’s in it.
So this litterally is down to every bolt, whatever
you need. The primary things we’re looking at is
the o-ring, the impeller itself, which is your
most common wear item, the stainess housing that
the impeller rotates inside, so they are the two
items that wear against each other, obviously with
this being stainless it is the rubber impeller that
wears more rapidly, but these can suffer corrosion.
There’s the base plate that the impeller spins on
at the bottom and then this is the actual pump housing
that the metal insert goes in. This is the woodruff key
that connects the impeller to the drive shaft, so
without this the two can spin independently
this is what locks the impeller onto the drive shaft
some washers, and then here is the little seal that
goes into the housing where the pipe comes out.
So we’ve got everything we need should there be
a problem with any part of this, so now that’s ready
lets take the leg off and see what condition this one’s
To get to the water pump which is sort of sitting up
in here, we’ve got four bolts, two on each side and
then we’ve got this locking nut that connects the two halves of the gear selector. So I’m going to
undo this locking nut a little bit down then wind this collar up, undo these
four bolts then slide it down. So here you’ll see now this collar has
been wound up so this is seperate
and these four bolts are out I’ll just start pulling the gearbox down
As things often are with outboards, boats
anything near water, this gearbox is
actually a bit stuck So if you’re sure you’ve got all the
bolts off I just give it a bit of a
tap with a hammer. Just be really careful,
this is just a plastic hammer.
This edge is quite thin, it’s tempting
to hit on that but you can really easily
break it so be careful there. There
is a little bit of a groove here where
water comes out so I’m going to try
a little pit of prying here with a
screwdriver as well. But just patiently
work your way around and see if you can
get it to come loose if you have this
problem. So I just gave it a few taps on
here with the rubber mallet and now it’s just opened up a little bit
so we should be home and hosed here.
And there you go.
I’ll give you a bit of an orientation. So you’ve got four ten millimetre nuts
that hold the housing to base plate here,
to the gearbox, you got this washer over the top that spreads the load, but you often don’t have this metal part that
comes up over thetop. This is that little rubber plug that
seals the pipe, the outlet from the water pump
up to the power head. And this is the drive shaft from the motor.
So I’m going to take these four bolts out
take this off, take the housing off and
you’ll see the impeller and everything
that is inside. Best way to get these pump housings off
is to get a little screw driver in and
pry it up a little bit. And the whole thing will slide up. Then
What you are left with is this base plate
we saw in the kit, the impeller, and inside,
connecting the impeller to the drive shaft
is the little woodruff key.
Now what you’re looking for with these
impellers, it’s the age that makes them
keep that bend, they are a tight fit, the whole purpose on them is to fit
inside this eccentic shaped housing, but you’re really looking for signs of wear
on the tips of these impeller blades. If they are getting thin, brittle
cracked, anything like that
to be honest with you once you got it open it probably is worth just
replacing so I’ll put the new one in while we are here you’re probably use most
of this hardware, I’ll clean up the
base plate and everything and then I’ll use the rest of that kit
on the older outboard and just buy in individual impeller,
none of the other parts for that So to get this off, once again I’ll probably just get a screwdriver
underneath it and just slide it up It can be worth cleaning this shaft
as it has to slide all the way up the
drive shaft and off the end so if this is a bit corroded and a bit rough,
giving this a bit of a clean can help you
slide the old one off and the new one on. This shaft isn’t too
bad so I’m just going to give it a
wipe with a rag and a bit of brake cleaner If yours is quite corroded
a really fine, fine grit emery paper is not gonna hurt. This section doesn’t
turn on anything or anything like that. these impellers are quite a tight fit so
don’t be surprised if it takes a little bit of effort to get it up the shaft.
It’s locked from turning but it’s not locked from sliding up at all. Sorry about the glare in this shot, I can’t
find a better angle with this vise where it
is. So, that’s the impeller off, the one we are
going to replace. It actually does have a bit of wear, a bit of debris on it. It is
used in very turbid, salty water which is
obviously a bit more abrasive.
I’ll show you here quickly though, If you don’t have a spare one
this is the little woodruff key
this is the key that causes the impeller
to spin with the shaft, so just be careful you don’t
lose that when you take your impeller off if you don’t have one the base plate is cleaned up
inside here is that inner housing we
were looking at before, that the impeller rubs against.
There’s nothing wrong with that, it’s in fine condition,
but what I will do is replace the o-ring here with this other o-ring just because I’ve got it here
so the impeller and the o-ring are the only two parts we’re replacing on this, and then we’ll put it back
together. I’m going to us a pick like this. Really
handy tool to have floating around just to fish
this old o-ring out.
Just a little bit of a wipe in the groove it goes
in. Here’s the new o-ring, I’m just going to put
a bit of rubber grease on it, just run a small
amount around. Press that in. I’m also going to take a small amount of this
rubber grease and just put a really light smear
around the inside of this pump just so when
it starts up for the first time the new
impeller doesn’t get damaged.
you’ll also notice is there’s there’s
Now putting these impellers on, we’ll open
the other one, when they’re new, their
still pretty straight, then once they’ve
been in the housing for a while they get
this curve. What you’ll also notice is there’s the slot in them, if I can show you, there’s
slot along here which is where the woodruff
key goes in. That slot doesn’t go all the way to the top
so you can only put it on this way you can’t put it this way because the woodruff
key will hit the backing here so make sure
you slide it down the right way. Then, if you look at the way the old one went,
so in this case the slot is at the bottom so
I know it went this way, you’ll see that
Yamaha motors turn clockwise.
00:35:52,650 –>00:35:59,180
As it turns pushing those, imagine it turning clockwise it’s pushing these blades back this way.
That’s important information for us to have
Oh, you can also make it a bit easier by putting some grease
just inside the help it slide down the drive shaft
a bit more easily.
Another tip, again, when you look at this woodruff key slot, you’ll
see it is aligned with this blade, so when you’ve got it turned upside down if you keep an eye
on this blade you’ll know where you’ve got to
align it with the key. So slide the new one down
align that blade with the woodruff key
and on it goes.
Now, the reason I was saying about the
Yamahas turning clockwise, is that what we’re going to do now, is that these blades
are wider than this housing, that’s why
they bend like this. So as we slide the housing on the top
I’m just going to start turning these
blades clockwise by turning the driveshaft
clockwise. so as the blades coming to the housing
they aren’t in going to the housing facing one way and then
expected to flip the other, they’re facing the way to the boat will naturally want them
to turn. All right, now, I’m just going to
do these 10mm bolts up again. When it comes to tightening these bolts,
what we’re looking for is an even pressure
so I’ve got them all nipped up now and I’m just going to go slow around and give
them each a bit of a tighten until they
feel even and pretty snug. We’re not looking to snap
the heads off the bolts. I actually don’t have a torque setting off the top of my head for these
but snug and even pressure is really what we
are looking for here.
All right, lets pop this gearbox back on.
Slide it back up. Sometimes you will have to jiggle these a
little bit, for a couple of reasons. One is that the hose that takes the water
from the pump up to the powerhead has to
slot into the pump itself obviously, and
the other is that the slines at the top
of the driveshaft have to align with the
female splines at the top of the powerhead,
but once they do, you’re all good to go. One thing I didn’t say before is that
I’ve left this particular boat in
neutral, so the controls are in neutral,
the gearbox is in neutral so all I need to do now is wind that collar
back on and it should all be aligned.
If you’re having trouble reaching that collar
you can put the boat in reverse which will bring the collar down and give you better access to it
and then the gearbox is in reverse, the
controls are in reverse, that’s fine
the only real issue is that when they go
back together they are aligned with each other,
synchronised. All right, and because you’re the do-it-yourself
type of man or woman, you’re likely to be
the next person working on this,
just put a little bit of this antiseize, this is the type of antiseize used on aluminium,
don’t use the copper stuff on aluminium.
Just put a little bit on each bolt, because the bolts down the low end of this
housing can get corroded and you’re just making
life easier for yourself next time round. So I’ll go around and put a little dob of
antiseize on each of these and do them up
and then I’ll tighten them up again.
Next thing I’m going to look at is the
thermostat. The thermostats open up when the engine
gets up to temperature, well, the water
gets up to temperature and allows water to circulate through the jackets that cool
the engine so when the motor starts the telltale will start running straight
away, even if the thermostat’s closed but it’s only when this thermostat
opens that you’re really doing any
cooling of the engine. So also just be aware if you gonna check this that you’ll
need whatever little gasket goes for your thermostat because there’s a really
good chance that when you take this cover off this thermostat if will tear
even if it doesn’t, you know, it needs seal well otherwise you leak water out
here and you’ll start shorting out HT leads or whatever. So this particular one
just has 3 10mm bolts. So I’ll just put this camera down and
take these off and then we’ll test
the thermostat. So once our bolts are off, this top’s
still a little bit sticky. So it’s actually got a little lip
under here so we’ll just push up
this way, there we go.
So cover off, thermostat sits in here,
lift it out. Yeah, it’s a little bit
crusty, once again I think it’s been
sitting for a while but we’ll clean up and go test it
So you’ll see here the top of this
is thermostat closed moment so just got a bowl of water out of the
kettle and we’ll pop it in.
We’ll see if this water is hot enough
to open it. You can just see the top rising up now so we can pretty much give this one a
clean bill of health to be really scientific about it you can
put it in cold water and then slowly heat the water with a the thermostat in it
and see the exact point it opens
but I think that’s good enough for me. The biggest problem is if they’re just completely
seized shut and you never get the cooling water through the outboard. This thermostat
gasket in really good condition so I’m gonna leave it on. The textbook will
tell you to replace it
every time and certainly have one with you because if it does tear or gets even
just the surface turn off it, this one’s actually a really good condition so I’m happy
with that, but you won’t really be able to use
the boat without some sort of suitable sealant
or a gasket so have one even as a backup but you know, it’s not a spare part that’s going to
deteriorate on the shelf so save it for when
you need it. So pop him back in, put the cover
back on, tighten the bolts up and I think we’re getting
ready to give this a running test now Well, that about wraps it up for today
I hope this video helped you if you are looking
at servicing your outboard yourself.
I did actually end up filming changing the oil in a four stroke
but the footage wasn’t really usable
so apologies for that not getting included here but I will do a suplimentary video to go with this for people who own four stroke outboards some time
So anyway, I hope you enjoyed. If you did please
rate, comment and subscribe and I’ll catch you next
time. See ya.


  1. Want would cause my to have to push and release my choke to get any speed from my 80 hp 1987 Mercury. Starts and run good at low speed

  2. Great videos.All are helpful.Have a general question.I have older Johnson outboard(80's) .Should I be able to move fly wheel back and forth say less than a tooth width without anything else moving other than the Crank.I was concerned I could have connecting rod slop to the crank.Motor runs pretty well.

  3. I have a 2 stroke 15hp yamaha I have gluppy oil coming out of my prop from my exhaust the oil seals have been checked and pressure tested so that's ruled out. Could it be my mix is to oily or what else might cause that to happen cheers mate awesome videos by the way

  4. Your videos ,are always well detailed and explained ,in a professional simple and straightforward manner,Just the ticket!!!.

  5. I know how much longer the actual job takes when you are also filming so thank you! Then you had to edit it! So a list of your favorite greasing compounds?

  6. Thank you for learning a lot about major problems with outboard motors. I can now use my outboard motors more safely and fix small repairs by my own.

  7. One thing I would have done ,when you had the impeller housing and impeller off I would have lifted the stainless plate off and cleared all the salt residue to make a better water flow just saying!!

  8. It’s only because I did mine the other day and it was bad for a engine I always thought I looked after ! Superb all round mate 👍

  9. Hey i hope all is well. Do you ever work on force 125hp motors by chance? I have 2 1987 Force outboards, one Force motor came with my 1987 Bayliner Cobra and I found the other one for $100 and they both run luckily. I just want to service and rebuild whatever it needs, do you have any videos on those motors? what are your opinions on the Force motors? thank you for your time!

  10. Great vids what a help. What happened with the 30 that had the compression discrepancy?
    I have one of the same that turned up low compression, so I replaced the pistons and rings.
    Then after an hour or so in the water and standing for two days, it battled to pull. Salt water has got in through a corroded water jacket in the block at the cylinder head gasket. The pistons look reusable, and I have found another block in much better shape.
    My big dilemma is the crank.
    The bearings don't feel great, but I see the whole unit needs to disassembled at an engineer to get at replacing the big ends and other central crank bearings.
    Any shortcut suggestions? A new crankshaft assembly would be far too much for this old motor.

  11. Forgive me if you've covered this. I have been given an evinrude 30. It looks very neat. Only ever run in freshwater. Last used 6 years ago.
    What should I do before running it? Drop some 2 stroke down the cylinders and turn it over gently? Any other thoughts?

  12. Really found you video excellent but for one problem. You captions often covered the area you were working on which made it hard to get a visual. Apart from that great and thanks for taking the time to do the videos.

  13. wish you would do a video on 4 stroke outboards making oil. I have a 2013 Yamaha F70 that I purchased new. Broke it in just like the manual said. Never had a problem for the first three seasons. Then last year after winter I hooked the hose to it and started, let it run for about fifteen minutes. I turned off and when I pulled the dipstick the oil was all the way up the dipstick. I drained the oil into a bucket and the changed the filter and put new oil in it. The used oil smelled like gas was in it. This engine has about a 100hrs on it and it doesn't stay in the water. Found out from the mechanic at the dealer they had the same problem on their rental pontoon boats because people just put and never run them hard. Now I run it at higher RPM's for the first 15-30 minutes and it does seem to take care of it. This is not just a Yamaha issue but happens to many manufacturers. Any thoughts?

  14. You make everything so much easier to understand for the layman. Very much appreciate your clear approach to tackling tasks. You're a good channel to find!!!

  15. Good Video on outboard maintenance. It's good for the DIYer that owns a motor.
    I was surprised that you didn't use a little grease on the prop shaft, when reapplying the propeller. ?? If not, then explain why.
    Keep the Videos going.
    THANKS Again.

  16. thank you very much for video. just wondering would a Yamaha 15hp 15D 2001 top half be interchangeable with a 1990 15D ?

  17. Thankyou, really informative. I want to have a go at the pump impeller, but before this I had no idea where to start.

  18. Hi Mate, great video thanks for the time posting. I am mechanically minded but this step by step video helped me understand much better. Thanks again. Regards Brook Oyster Bay NSW Australia.

  19. Following these videos diligently thanks. But 1 question I have replace a water pump on an Evinrude 15hp about 25 years old. I do need to service engine and check thermostat change sparks and such. As it doesn't idle.
    But question is I was very cautious replace the water pump with the kit there was not gasket between the metal plate and the plastic cover over the impeller on original and no gasket in kit. Put it together and started motor now I at least have a very low water flow, there was none before but I hosed out the intake and water came out the nipple freely. Could this be that the engine isn't getting to running temp or should there be strong water flow from the start?
    Love to run the motor up to you but it's the only one I have and am to unfit to row from Church Point!

  20. I just got a Ranger 395-vs with a Evinrude 225 V6 that hasn’t ran for 12 years and thanks to your video I know where to start. Thank you very much

  21. Thanks for all the great vids, Stu. Think i've been through all of them now and some a few times. Informative and entertaining!

    Got a couple of boat projects underway and want to service the motors for them, this vid is very handy! Wondering if there is a place to get a "full service kit"? I can't see them listed as such on and i'm not sure of all the parts i need to order…
    Have a '97 25hp Mariner Marathon, a '91 Suzuki DT40hp (with Yamaha cowling on it) and an as yet unkown 60hp Merc (on project boat i'm probably picking up tomorrow).

    Also publicly embarrassing myself by documenting the projects on Youtube…

  22. Without doubt the best outboard maintenance video I’ve seen, clear and concise, terrific for any boaty, thank you.

  23. WOW! I didn't know anything about Outboard Motors until I watched this video. I'm no expert but at least I know what to lookout for if and when I should by a boat! I wish you were here in the States mate! Cheers to you!

  24. Thanks for a great video. You had mentioned including a link for the pressure tester for the gearbox but I couldn't find it.

  25. Hi, I have a problem with a boat I brought. ( Outboard 60 HP Johnson About 1982 2 cylinder ) It has a problem with ventilation. I think it is because of the setup of the motor. the transom does not slope in like most transoms it is very square with the keel/hull. it looks to me that the engine needs more Negative trim but it is trimmed all the way down. I hope that all makes some sense. I am thinking of buying some wedges to pack out the motor to increase the negative trim. Do you know of a way to check this?? Does the cavitation plate need to run on the same plane as the Keel/ hull? My propeller slightly faces pointing up to the surface of the water. The motor slips like a car with a bad clutch. ( I have tried two different propellers and both are the same. Fairly sure Propellers are not spun and it good condition ) The cavitation plate it level with the keel of the boat.

  26. Wonder how man THOUSANDS of dollars/rupie/GBP you've saved viewers.
    Answer: LOTS
    Thanks for a great video.
    More confident now servicing my motor.

  27. This video is great! Lots of good information. I actually have mine partially torn apart for maintenance. I'm waiting for parts. Thanks for posting it.

  28. Hello. I have a Johnson 6hp, Seahorse. Year 1976. I did a compression test, only gave 70 PSI both cylinders the same. Can It improve noticeably if I only substitute the rings? But only 0,03 oversized rings available. Thank you for tip.

  29. I'll be doing this myself, thanks to your Videos.not scare anymore. Yamaha 225 HP and Evinrude 25 HP Outboards.

  30. love your video just wish the writing wouldn't block what your doing . i lean more by seeing and hearing you , keep up the teaching.

  31. Great video once again mate I would bet the ones who gives thumbs down couldn't service there lawnmower never mind outboards

  32. If the motor had been sitting for several years when you pulled out the spark plugs, would you spray a bit of penetrant/lubricant into the cylinders? Or, is that a no-no ?

  33. Hi dagnar marine I’m from Northern Ireland and recently just bought a 60 hp mariner 2 stroke. I took it out the first day it went fine for a minute or two and then it died down to a few knots we checked all the obvious things and realised it might have been old fuel. We flushed it out but ever since I’ve took it to the water it will start for a mintute and then it stalls and won’t start again it’s starts in the shed fine but the moment it’s dipped in the water I’m having issues. Weird that it at least drove the first time in the water but now I can’t even get it into gear when engine is submerged any ideas would be appreciated

  34. Excellent video. I really appreciate the clarity of both the videography and your easy-to-follow instructions. As a first time boat owner, this gives me confidence to tackle maintenance tasks that were a mystery to me. Thanks again!

  35. Have had my Evinrude since 1987, bought new, never paid any attention to it due to it operating perfect but now I can get familiar with it. It is like a new toy for me to rediscover.

  36. Great video thanks! Can we have a link to the video where you make the gearbox pressure tester? Is it a hand pump brake bleeder or something else entirely?

  37. Hi there,

    very informative video!

    Have an old outboard motor with a strange tick in it. never worked on outboard engines so little knowledge.

    Have a MAC 3 type TA636 / FA1200

    start fairly easy but then makes a strange sound, made a video of it would you like to check it out?

    Can also find very little information about the engine.

    according to the internet i have a tecumseh engine ta636

    hope you can help me out !!

  38. As others have noted here, your videos are very helpful and clear. Keep up the fantastic work. I am a lady who can put together an aircraft engine but did not know squat about servicing outboards. Thank You.

  39. Did you ever make a video on changing an oil pump on a 4 stroke? I live where it’s far from any service place and unable to find directions for this. Thanks

  40. I will be attacking my first lower unit on Yamaha 50 2 stroke in 2 hours. I think the impeller is shredded. What a great help this has been for me.

  41. Thanks for great video, I am from Qatar, after giving speed and then 5 mnt good but after Come slow,,, what can be problem

  42. Thank you for posting all those interesting video's at Youtube!
    I've also got a question about a Yamaha, 40hp, 3 cycl, 2-stroke, outboard engine.
    When this motor is in forward gear the RPM is not stable.
    What's the right way to adjust the idle-mixture-screw of all 3 carburators without using a flowmeter (carburators have no connectionpoints for vacuumgauge)?
    The Yamaha servicemanual says "turn pilot screw in until it lightly seats and then 1 1/8 turn out".
    Or do I have to adjust each carburator until the highest RPM?
    Or do I have to turn the pilot screw clockwise untill it the engine stumbles, turn it counter clockwise untill it the engine stumbles and take the middel point of those 2 points?
    How do you do this?

  43. I've watched several of your videos and found them very helpful. One thing I learned, especially working on 2 strokes, is to check compression before performing any other service. I appreciate your taking the time to make these videos and I think I speak for most when I say THANKS!

  44. I picked up a 1978 merc 7.5 it has a propeller with 2 blades which is beaten up I am using it on my hydro force inflatable boat speed sucks not sure if it is the propeller or the engine any suggestions. Engine stalls at idle not sure if it is common with these motors.

  45. Thank you. All your videos are great and have finally helped me brake the mystery of marine outboards. I now feel confident working on my old engine and servicing it. Also, through watching you’re previous videos you’ve generously passed on a huge amount of knowledge that will enable anyone to buy a second hand engine with confidence (knowing what to look out for) and to deal with dealership repairs or servicing, especially when getting the feeling you’re having the wool pulled over your eyes or being fleeced, unfortunately this happens from time to time. 👍🍺👏🏻

  46. Thanks a lot for that video! Its a great help for an amateur like me – now I will maintain my outboards all by myself! That will spare a lot of money and the my understanding of the technique of that engines is much, much bigger than before! Thanks again!

  47. Hi how are you, I would like to ask for help, I am looking for the service or repair manual of a 1992 Mariner 55 EL engine 2 times, 2 pistons is Yamaha engine, I can not find a way to repair it thank you very much for your videos.

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