yanmar 1gm10 starts but wont rev help

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cat5cable

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www.cat5cable.co.uk
hi our 1gm10 starts but wont rev then it will not tick over and finally stops, restart it and it fires up again but then dies, i have checked fuel filter and its clean and looks ok checked and i undid the fuel pipe which sits on top of the injector and turned engine over and fuel spits out so i am rather baffled, could it be dodgy fuel?? i have sworn at it many times but still no joy.
thanks
tim
 
Some article in a past issue about these fitted in catamarans has a bearing on your problem. The alternator field wire needs to have a switch fitted apparently to disable the unit so that the engine can summon enough energy to start with cold oil.Anybody else remember this article, read it today in the barber's as about twelve of us lined up for the bi-monthly harido. not cheap anymore at €10 adding to this the cost of parking the car at the meter for ages.What is life coming to!
 
Yes and I see your nick is Cat5 so maybe it is the port engine, the other one has a relay of some sort to prevent this happening.
 
I would have thought it was more likely to be a fuel problem:
1. Pipe blocked with sludge
2. A bubble of air difficult to bleed out stuck in a loop of pipe
3. A leaking fitting, leaking air into the pipework somewhere every time the engine is running and sucking fuel.

For the time it takes to mess about guessing, I'd strip out the complete fuel line, clean the pipes with a tiny scrap of rag on the end of a long piece of wire and remake all the compression joints with Hylomar (and new olives if the old ones have been squeezed beyond redemption).
Don't forget to check the seal on the engine mounted fuel filter bowl, as that seems to be a bit of a pig even for Yanmar to get right on a brand new engine - ask me how I know....
 
I have a Sterling alternator controller on my 1GM10 and a switch, to cut out the extra boost charging that this demands from the alternator. When I start the engine with the Sterling boost, it to starts and dies and has great difficulty getting going. However, if I cut out the Sterling's boost (i.e reduce the field current), the engine has enough drive to pick up and get going, then I can switch the Sterling boost in and everything is fine.
 
Two suggestions.

Possible minor air leak in the fuel system that is only affecting fuel flow above idle speed - in particular check banjo bolt connectors as they can work loose due to vibration on the 1GM.

Alternatively - have you checked the air filter? I have seen a 1GM where the metal cone that supports the foam filter was put in the air intake casing the wrong way round and the foam filter got sucked into the air intake partly blocking it. The engine had similar symptoms to yours. Enough air could get in to start the engine but it would die if revved.

Best of luck.
 
The switch to disable the alternator is only used if the unit is a saildrive. No such thing on a conventional drive. Everything points to fuel. You don't say if this is a new problem. If it is then dirty fuel or air getting in are the usual suspects. Change the filters and rebleed at every point. Remove the air filter to check the foam insert - even start the engine without it to ensure it is not air restriction. Noisy but harmless. Also check that the fuel shut off is working properly - that is it goes fully forward when you push the stop cable back.
 
One important point.Compression fittings must always be assembled dry with new olives if at all possible.In order to rule out(or in) the fuel supply system you could rig a simple temporary tank and feed the fuel by gravity directly to the injection pump.If it starts and runs,just move the feed up the circuit to the primary pump,then to the filter housing and so on.If it keeps working the problem lies elsewere.If not then you know.
 
just a thought.......i presume you've checked the obvious that the butterfly is opening okay with the throttle and that the stop cable is not pulling the stop lever?

my stop lever stuck once and i got the same symptoms..........a bit of fuel to start with but not enough to run
 
[ QUOTE ]
One important point.Compression fittings must always be assembled dry with new olives if at all possible.

[/ QUOTE ]
I've often heard that said. I've never taken any notice of it, but then I was taught to make compression fittings at the Rolls Royce training school in Bristol, and what the hell do they know about anything like this. /forums/images/graemlins/smile.gif
 
But the initial replies are correct. If a cold 1GM or 1GM10 is connected to a healthy but discharged battery , even the standard alternator will stall the engine if it is put into gear before it has warmed up and charged the battery somewhat.

I would add my additional checks to the list - issues I have seen the other week:

1. Stop cable jamming - it was holding the lever open slightly until it vibrated back to the run position .

2. Dirty injector caused by too much running in black-smoke mode (I was pushing head on into a F6-F7 for two hours the week before, coming back from a race in early February).

All I do these days is remove the injector and carefully scrape off the face of the injector without messing up the pin in the middle using a stainless steel (soft) screwdriver implement on a swiss army knife.
 
Many years ago, a friend had a similar problem. After months of us tearing hair out, it was,
The dip tube in the tank was about 6mm i.d.
But then in his wisdom, my dear chum, had installed a fuel shut off cock before the filters etc.
But, it only had a bore of about 3mm.
This of course took very little blocking, and it periodicaly did.
Blowing back produced the illusion of a clear pipe, but the tiny plug was drawn back, to block the 'cock' at the next attempt to start.
Almost certainly a fuel problem. Bill.
 
I second the sugestion to use a temporary tank placed above the engine to provide a gravity feed system. This should keep positive presure on the supply pipes which will stop the problem of micro air leaks.
 
Look for tiny air leaks in the fuel system. Wipe each joint dry, not forgetting fuel filter seals, and air bleed screws. Start and run up the engine several times. Now go round again with a coloured tissue (pink loo paper does nicely!) and wipe each joint carefully again. Any fuel that has leaked will show up in the coloured paper clearly - and will be admitting air, stopping your engine. Talc works well too, but is messy!

Just because the injector pipe is delivering a few squirts of fuel, it doesnt mean all is well. Enough fuel reaches the engine to start it, so there must be fuel present at cranking speed. At running speed, insufficient fuel is getting there to keep it going or to allow it to accelarate.

Consider too partial blockage of the fuel pipes preventing sufficient flow to feed the engine, or the fuel tank breather may be blocked preventing fuel from being lifted from the tank.

The fuel lift pump may have a pin hole leak in its diaphragm, or a faulty valve, which will produce exactly the symptoms you describe.

It may also be an injector pump fault.

If it was the alternator, then it would always do it, nor should it prevent the engine picking up when you open the throttle.
 
well we tried all day saturday drained fuel tank and filter all new fuel bled system but she still wont go same as before starts then stops, well we have only got one more week before she goes to her new owner so we have employed the boatyards marine guy to sort it.
Again thanks to all

tim
 
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