Yanmar 1GM10 injector

[masca]

Hi. I have a Yanmar 1GM10 that won't start. It used to start very well and is still turning over as normal, but it will not fire up. We have bleed the fuel system, but with no result. The injector is squirting out fuel, but not not very much (just little bursts of fuel), and it has been suggested that the injector needs servicing (I don't know the exact age of the engine, and if/when the injector was last serviced). We have removed the clamping plate, but the injector is stuck fast. Can anyone please tell me whether it should screw or simply pull out? Is a special tool required? TIA.

 

[richardabeattie]

Did the fault come on suddenly or develop over time? Is the air supply/air filter OK? Is the unused fuel arriving back at the tank via the low pressure piping?

 

[andy_wilson]

How do you know that the injector is squirting out fuel if you can't remove it? If you mean the fuel pipe is delivering small pulses of fuel, that's a start.

Most injectors just pull out (I am not familiar with your engine though). If there has been a bit of blow by it will get bonded by a carbon like laquer that takes some shifting. Soaking with diesel over a prolonged period (weeks) got mine free (Volvo-Penta - have to take care not to disturb the copper sleeve in this design).

Once well soaked I gently got mine moving by using a spanner on the flats where the clamp fits, gently turning this way and that until it loosened.

IF you get it out you could try connecting the pipes up back to front to witness the injection pattern. Tiny puffs of diesel mist are correct, dribdles or jets indicate an injector requiring service. Beware, don't get within a couple of feet if you try this, in case you get a high pressure jet in the eye, or if at close range, injected into your skin!

 

[masca]

Thank you for your very quick response! Yes, the air supply/filter seems fine. We have tried turning the engine over with the filter removed, and it still does not fire. We have also tried 'Quickstart' with no luck. The unused fuel is returning. The problem started suddenly. Thanks again.

 

[masca]

Yes, I do mean that the return fuel pipe is delivering fuel, not the injector - sorry, I'm afraid I am very engine-stupid! I would definately describe the output as 'sqirts' as apposed to 'mists', and not very powerful. From your description, it sounds as if servicing the injector is the way to go. Thank you.

 

[TheoSr]

If it does not start on Quickstart, ther cause is not a lack of fuel.
How about the compression?
I remember a Yanmar that ran as usual one weekend but refused to start the next weekend. No compression. Valve seats and head were cracked.

Good luck!
Theo

 

[pampas]

to remove a stuck injector, PUT the holding nuts ON until full engagement of thread is obtained make sure a gap exhists between lug and nut. Try to start ,but do not allow to run for more than a few seconds. compression will blow injector loose. an old dodge we used at sea, but be vigulant. When replacing I suggest that in this case you renew the copper washer rather than anneal it.

 

[Mal113]

The fact that you have tried Quickstart and the engine will not start and the fact that it happened suddenly, suggest to me that it is not an injector problem. You state you have a return flow of fuel, this would suggest the equipment from the point you see the return fuel back via the injectors, fuel pump, lift pump and filters would seem OK. I am not familiar with the 1GM10 engine but I would suggest taking a look under valve cover to see if the valves are being opened and closed it could be the gear train has failed, this would result in the injectors not being opened to inject fuel, nor would the valves operate.

 

[jerryat]

Hi. I shall be very interested in the outcome of all this excellent advice, as a friend of mine has exactly the same problem on exactly the same engine.

We eventually managed to start it on Saturday by holding a small gas blowlamp near the air inlet until it fired up, but this followed checking that the fuel was flowing properly to the injector, the return fuel line was ok and the valves/tappets were ok. He had three fully charged batteries and the engine spun over very briskly - but to no avail.

The thing that has baffled my friend is that the engine worked perfectly the last time he started it!! Since then the boat has been lifted ashore onto her trailer for the winter, but that's the only difference.

He doesn't have a pre-heater (says it isn't an option) but obviously doesn't want to use a blowlamp each time!!

This is a real baffler.

 

[alan8376]

If this had been a diesel car! I would have said engine is Kn@@! Usually, if a diesel starts with warm air. It is a sure sign that compression is down! Maybe piston rings??

 

[Col]

How long since it was last started? Could you hear the engine compressing as it turned over or did is spin with little resistance? I would probably be looking at something other than injector to give the sudden failure to start. Valve stuck maybe? It should of fired when you gave it a sniff of ether if everything else was OK.

 

[Birdseye]

[ QUOTE ]


The thing that has baffled my friend is that the engine worked perfectly the last time he started it!! Since then the boat has been lifted ashore onto her trailer for the winter, but that's the only difference.



[/ QUOTE ]

Thats your answer. A diesel heats up its charge to the point where it burns by compressing it. If the air / diesel charge is much colder to start with (as it will be with the boat now out of the water and the first winter frosts) then it may not reach temperature without help. You could even have the diesel waxing because marine diesel isnt doped with the winter anti waxing agents like road diesel is.

The first thing to check is the tappet clearances. If these have closed up you could be losing compression because a valve isnt seating properly.

It wont help that the likely cranking effort of a cold battery will be less and the drag of cold lube oil will be greater.

The Yanmar engine doesnt have a cold weather starting device so it will be much more difficult when really cold.

 

[vyv_cox]

Always look at the simple things first. Don't jump in and start taking things to bits before:

Make sure the decompression lever has not been pulled.
Make sure that no electrical connectors have fallen off anywhere. There may be a solenoid valve controlling fuel supply.
Is the exhaust clear?
If all these are OK, take off the rocker cover and make sure the valves are going up and down and that there is clearance at the tappets at the appropriate times.

As others say, if it won't start on Easistart there is either something seriously wrong, unlikely in the circumstances, or something such as the above.

 

[Honey]

The one big problem with these engines is the exhaust elbow blocking! If no exhaust can get out then air can't get in. If no luck try the Yanmar help line at
http://www.freeboards.net/?mforum=yanmarhelp

 

[jerryat]

Hi Birdseye,

I take your point, but for the last few days down here in Devon we've had temperatures in the teens, so hardly cold enough to affect 'normal' starting. As I mentioned, we whipped the rocker cover off and checked the valves/springs were operating correctly, and that the tappet clearance was spot on.

As I also mentioned, with three fully charged batteries cranking the engine very briskly, it should have started relatively quickly. But it just didn't want to know until we used a bit of heat.

I suppose the thing which puzzles us most, is that when the engine was lasted started/used it was perfect (very similar temps etc) but a couple of weeks later - nothing.

It could be compression I suppose (the injectors were out and serviced two years ago so should be ok) but even if a little down, the damned thing should still have started we reckon.

As I say, a real baffler!

 

[andy_wilson]

Not necessarily, the fuel supply and return lines will just pulse fuel, the injector tuns this into a mist, and is unlikely to deteriorate rapidly.

At least you know the fuel side of things is reasonably healthy.

Is the stop control still connected and operating correctly?

I would try a few other fundamentals before taking the engine to bits. Experience shows that the stuff inside the engine is probably the last to go wrong.

 

[Birdseye]

All you need for a diesel to work is air, fuel and compression.

The air isnt likely to be a problem. Fuel could be if the lift out has caused air to get sucked into the fuel system. Or dirt stirred up. Or even the engine stop to be trodden on / pulled out etc But it doesnt sound likely from your comment about the injector spray.

The final possibility is compression and as Viv says the obvious culprit will be valve clearances and the decompression lever. It could also be wear - if compression is only just enough on a good day, then a bad day ..........

If its none of these then you are down to hiring a mechanic to come along and have a look. But dont rush to be a mechanical hypochondriac - all diesels without heaters are more difficul;t to start when the weather gets cooler, but if it does eventually start then why worry?

 

[mikejames]

I thought on the Yanmar the return fuel is meant to be from slight leakage due to fuel lubricating the injector. On a working engine the fuel should be mostly going out of the injector nozzle not pulsing visibly from the fuel return pipe.

Sounds like if you are seeing pulses of fuel on the return pipe the fuel is not opening the needle but instead leaking around inside the injector. Something like a piece of dirt has got in, and the injector is a bit stuffed..

This is a bit more critical than the usual injector cleanup. Never mind a new injector is less than £200.
I got mine out once by loosening the clamping nuts somewhat and turning the engine over.
Alternatively getting a spanner on the flats and trying to turn the injector may work.

The copper washer and heat resistant washer in contact with the injector face will need to be replaced anyway.

Go and visit http://www.yanmarhelp.com/

 

[pete]

I also have a 1GM10 and agree with Forethought_of_Gosport nothing goes back through the return on my injector.
A few years ago my engine became a pig to start when cold but once started ran perfectly after a lot of messing about with bleeding diesel, compression test, valves ect we removed the injection pump and noticed that inside the engine there was a link to the pump from I think the governor on the crankshaft which gives you more diesel for starting, once started it is then disabled.
This link had stuck in the off position and by prodding it it sprang back to the rich position after that it has started perfectly.
The annoying thing is that this link can be reached through the oil filler hole without any disassembly at all. Just a thought.

Pete

 

[masca]

At last we have resolved the problem! The engine is now running again after fitting a replacement fuel pump and spending a good hour with a blow torch! We hadn't suspected the fuel pump, as we could manually pump the fuel all the way to the injector, and everything looked OK. However, we have since learnt that, whilst the pump might look as if it is working correctly with the return pipe loosened off, this does not mean all is OK once everything has been reconnected! Thank you all for your help and suggestions.