Hey there, Dangarstu here. Today's video's on what to do if the speedometer on your
outboard motor stops working but the gauge itself is still lit up, has power et
cetera, but you just showing 0 knots wherever you go.
I didn't really plan to do today's video, it end up being bit impromptu
because I had a boat come into the shop that had this problem so I thought I'd
take the opportunity to film it so I apologize if it's a little bit scrappy
but it's only a short one so bear with me. The outboard on this boat that's having this
trouble is a Yamaha 60 AET, but a lot of outboards use a very similar mechanism
particularly the rest of the Yamaha range.
To get better access to the part of this outboard that's causing the problem I'm
just going to trim it up.
So if we come down here to the gearbox and if we come to the water intake and level with the
top of the water intake we come to the leading edge you'll see there's just a
really small aperture right on the leading edge of the gearbox and that's
where the water goes into as you're traveling through the water and the pressure that
water creates is what the speedo translates into an estimate of how fast
you going through the water. That's a very small little aperture and gets blocked
really easily. So what we're going to do now is unblock that. As with the telltale there's lots of
tools you can use to unblock this but I've got here is just a drill bit inside
a sort of a pencil collet. I've just got a little one mil drill bit in this, but about
1.5 is actually perfect if you can find one. You can see how much junk's coming out
of this hopefully. I'll see if I can zoom you in a little bit.
This drill bit's just starting to free up now and you can see some fluids coming out so it's obviously unblocked now.
And you can see how far it goes in, pretty much the entire length of
this drill bit, so probablu about 40 millimetres or something. That's definitely unblocked now so the next thing to do is
put a bit of compressed air into that hole to clear it out completely now that
the bulk of the blockages it away. You just need to be really careful you never do
this with the hose connected to the actual gauge because if you do that
gauge is very, very sensitive. they're quite small subtle pressure differences that
equate the various speeds on the speedo and they're nowhere near the amount of pressure that an
air gun like this will put through it so make sure you never did its kind of the big no no
here, but what we will do is disconnect that little tubing that comes from that
hole up to the speedo and that way we got no chance of damaging the sensor
in the speedo. From the outboard leg here you'll see this flexible hose going up, and this is
just hollow tube. Quite often there's a joiner right here on this particular boat
the joiner is round here at the tilt tube. So here, I'll just see how tight this is, there we go, that's disconnected. So this clear tube is the one that
goes up to the speedometer on the dashboard. It's not always clear of course
it just is in this case, and this is the one going down to the foot of the outboard
that connects with that aperture we just cleared out using the drill bit. So I'm going to
go down to the bottom and blow some compressed air into that little aperture we
cleared out and we'll see if anything comes out here.
So I can see a bit of fluid here so I'm guessing that's clear through if that came out so we'll put
it back together and give it a test on the water. Now, although this is the most common
cause of this problem is getting that little aperture block up, it's a bit like
pitot tube on an aircraft if you watch any Air Crash Investigation, that's
where I found out about them anyway, but it's not the only thing that can go wrong obviously any
sort of break in that hose, it means that pressure is never gonna reach the gauge or
even some sort of splitting the host will stop that full pressure reaching the gauge so if
you find that it's reading a lower speed maybe look at just replacing that hose
if you found this to be completely clear. The hose on this boat looks a little bit
affected by petrol or perhaps even a little bit of perishing from being in
the Sun so it's not a bad idea to put a bit of fresh hose every now and then if
you do rely a lot on this speedo. So these speedos work very similar to pitot tubes in
aircraft. If you watch any air crash investigation you've probably heard of those
and they work by measuring the pressure so as the boat moves forward through the water the
water coming into that aperature compresses the air in the line and then sends that pressure up
to the speedo on the dash and that's where you get your reading. The important
thing to be aware of with those is they don't give you speed over ground they give you
speed through the water so if you're heading into a current, your speed will
say it's higher than it really is and if you're flowing with the current it'll
say your speeds lower than it really is. So if you're looking for an accurate
indication your speed I recommend using a GPS but the speedos comes standard with a lot of
boats so why keep it working. Let's get out on the water and do that test now. Even the kookaburras are going to bed now. Unfortunately with winter coming it's getting dark pretty early now.
This morning that was giving absolutely no reading at all, and now it seems reasonably accurate. So sorry about the dim light, I think we'll wrap it up here. I think we can call that a success. So it goes to show that more often than not, I would say 9 out of 10 times, it really is just that little aperature
blocked and it's not hard to clear out. Well, thanks for watching, just a short one today. I hope you enjoy this video, I hope it helps if
your having this problem. If it did, please rate, comment and subscribe and I'll catch you next time. See ya!