Outboard Blues

[bigfatmatt]

I’ll preface this post by saying I’m useless with engines.

 

Last came to the boat 2 weeks ago (last week of June), engine ran fine. Most of the petrol was new that week.

 

Came back today and it absolutely doesn’t want to run — siezing up almost immediately.

 

I’ve attached a video, sorry about the shite quality. https://www.veed.io/view/f8649539-96f6-4f41-b5a0-46b4e2e76a9f?panel=share

[Tony Brooks]

One thing for sure, it is not seizing up, otherwise it would not spin over the subsequent times.

 

Is there a spark at the plug(s)?

[john.k]

Fuel blockage ..?........clogged filter ......water in the fuel? 

[bigfatmatt]

I’ve primed it with the squishy primer thing (not sure about terminology).

 

I’ve attached another video with the engine cover removed, I can’t see a spark but I’m not sure where I’d be looking for it (I got this boat 4 weeks ago and I’m completely unfamiliar with internal combustion engines — trying to learn).

 

I don’t think there’s any way water would get into the fuel, the fuel tank has been properly closed and inside the rear under-seating storage which is dry.

 

https://www.veed.io/view/b7fdb2c5-fee0-4d8a-b694-941b4205a87a?panel=share

[john.k]

You must understand your boat............  before you cast off.

[bigfatmatt]

2 minutes ago, john.k said:

You must understand your boat............  before you cast off.

 

Agree with this 100%. I haven’t cast off yet, I ran the engine last time on the mooring for about 30 minutes a couple of times just to make sure it ran (which, perplexingly, it did) and put some juice back into the starter battery.

Edited July 16, 2023 by bigfatmatt

[Alan de Enfield]

12 minutes ago, bigfatmatt said:

 

Agree with this 100%. I haven’t cast off yet, I ran the engine last time on the mooring for about 30 minutes a couple of times just to make sure it ran (which, perplexingly, it did) and put some juice back into the starter battery.

 

Not linked to the starter problem, but you MUST ensure that as soon as the engine starts you check the 'tell tail'. This is a small, but noticable, jet of water which comes out under the engine and looks like the engine is having a 'pee'.

 

This shows that cooling water is correctly circulating - if there is no tell-tail then your engine will over heat and sieze. The is a small pump in the bottom of the engine leg which has a rubber impellor inside it, if the engine has not been run for some months (say 9+ months) then it is possible that the impellor has dried out and 'stuck' to the inside of the pump, this will rip the vanes (fingers) off the impellor and it will then not pump.

 

If you have a 'tell-tail' then you don't need worry.

 

The impellor is recommended to be replaced at the annual service, or, removed 'for the winter' and stored in a jar of oil.

 

 

This is my 'bad' (broken impellor) and a good one for comparison.

 

 

[zenataomm]

Have you turned the fuel on?

[Tony Brooks]

34 minutes ago, Alan de Enfield said:

Not linked to the starter problem,

 

 I don't think there is an actual starter problem. I get the impression that it tries to fire and kicks the bendix out of mesh, as is normal. On at least one attempt you can see the torque reaction waving the motor about.

 

I think it is either a weak spark or a fuel problem. and checking the spark is probably the easiest.

 

It seems to be a starting problem to me.

[jonathanA]

It does seem to start and run briefly. It looks very similar to a yamaha 10hp on a friend's boat. That one has an automatic choke  I wonder if giving it a bit of throttle might be needed if the auto choke isn't working or not fitted.

 

Check.there's fuel at the little plastic filter on the left side of the engine when you pump the primer bulb as it seems to fire then stop 

[Mad Harold]

Looks like there is water coming out of the tell tale.

I think it fired but then stopped and I think you may need to give it a few more seconds on the starter.

A common problem is a blocked slow running jet in the carburettor. The hole in these is very tiny and blocks very easily. Needs removing and blowing out with a pump.

The hole is usually too tiny to push a wire through.This is not recommended anyway.

[Alan de Enfield]

30 minutes ago, Tony Brooks said:

It seems to be a starting problem to me.

 

Yes, that is what I said - as an engine 'novice' I was just explaining to him about the tell-tail (and I did say it was not linked to the starting problem)

[Tony Brooks]

15 minutes ago, Alan de Enfield said:

 

Yes, that is what I said - as an engine 'novice' I was just explaining to him about the tell-tail (and I did say it was not linked to the starting problem)

 

It is not that important, but you did not say STARTING problem, you said STARTER problem, and that might well send the OP down the wrong track. Hence I felt the need to clarify that point.

[Alan de Enfield]

1 minute ago, Tony Brooks said:

you did not say STARTING problem, you said STARTER problem

 

You are correct I did. As you say in that case best to make the  OP aware.

[bigfatmatt]

Thanks for all the responses, I did know about the tell tail and that’s working fine, good jet of water streaming out of the back.

 

Fuel is definitely on. There is definitely fuel in the tank which is max 2-3 weeks old. The squishy primer thing goes hard after a few compressions.

 

I’ve let it sit for a bit (assumed I might have flooded it by overpriming last time) and it’s started running (with some weird sounds) for a few minutes before cutting out. Video/audio: https://www.veed.io/view/fbc205a9-c507-4e9d-ac94-2cc81402d2e9?panel=share

 

I’ll try to find a manual and work out where the spark is but posting in case anyone has ideas from the sounds (I know engines talk, I just don’t speak their language yet).

Edited July 16, 2023 by bigfatmatt

[Tony Brooks]

Has it a manual choke (cold start enrichment) because it sounds to me as if you may have left the choke on by the way it runs well enough, then gets lumpy and lumpier and stalls.

[bigfatmatt]

I can’t see a manual choke anywhere on it, the only dial/knob I can see is the dipstick.

 

Anyone know how I could have a hope of identifying it and finding the right manual? Lol

[Tony Brooks]

Now we have a better idea of what the engine is, perhaps a member with specific Yamaha experience will give an informed opinion.

[Bacchus]

Does seem to be starting then failing which could well be the slow-running jet as @Mad Harold says

 

@bigfatmatt can you try starting it with a little bit of throttle? There should be a button on the throttle controller that allows you to move the throttle forward without clunking it into gear; I would try giving it a little bit of juice which would sidestep the jet or help clear a dirty plug

[BWM]

What looks like the air filter is very dusty and if so, could be plugged. Another thought is , has the fuel tank got an air vent that can be closed off - is this shut?

[blackrose]

I hope the OP doesn't mind me asking a question on the back of his thread...

 

When you don't use an outboard over winter is there any advantage in tilting the leg up so the prop is out of the water? I notice others doing this but I've always left mine in the water without any ill effects as I think leaving it vertical provides more physical protection from being hit by something than having it tilted & extended out over the water.

Edited July 16, 2023 by blackrose

[rusty69]

26 minutes ago, blackrose said:

I hope the OP doesn't mind me asking a question on the back of his thread...

 

When you don't use an outboard over winter is there any advantage in tilting the leg up so the prop is out of the water? I notice others doing this but I've always left mine in the water without any ill effects as I think leaving it vertical provides more physical protection from being hit by something than having it tilted & extended out over the water.

The small outboard we have has got an anode on it. I presume for the same reason boats so. I guess it will depend on the type of anode fitted, it's condition and the type of water. The wrong combination could be detrimental, but so could another boat running into it. 

[Alan de Enfield]

I was always told to tilt the outboard out of the water and let the cooling water drain out.

 

Reason : To stop the water freezing up and 'bursting something' in the engine or leg.

[bigfatmatt]

1 hour ago, Bacchus said:

Does seem to be starting then failing which could well be the slow-running jet as @Mad Harold says

 

@bigfatmatt can you try starting it with a little bit of throttle? There should be a button on the throttle controller that allows you to move the throttle forward without clunking it into gear; I would try giving it a little bit of juice which would sidestep the jet or help clear a dirty plug

 

I can get it running with or without throttle but only if we keep manually priming the fuel (10-15s after we stop priming it cuts out), so seems to be an issue with drawing fuel in manually.

 

Video: https://www.veed.io/view/38958e59-7796-4245-8112-ea9283a63dfb?panel=share

1 hour ago, BWM said:

What looks like the air filter is very dusty and if so, could be plugged. Another thought is , has the fuel tank got an air vent that can be closed off - is this shut?

 

Fuel tank has an air vent but it was open.

[Tony Brooks]

FWIW, I have known outboard fuel lines to fail around the bulb connection and less often at the O rings where they clip to the tank or engine.

 

Although this one seem to be a four stroke, the fuel lift pump is often operated by pressure pulses in the inlet tract or crankcase. The diaphragm and valves are often fairly weak items and can degrade.