Yanmar gm10 runs for a while then cuts out

[DoughMyDays]

Hi All.

I have an issue with my friends Gm10. We thought it was because the diesel ran dry but it looks pretty full.

We eventually with a struggle got the engine running. It runs for a few minutes, as its running, the pump of it seems to get slower and slower, as if its running out of energy until it runs so slow it then dies. I can then never get it started again.

I have bled two of the fuel limes which first got it started again, but The 3rd bleed screw looks like a big nut at the back. I managed to get diesel up to the other two bleed screws by pushing the the little lever. But I was a bit apprehensive about completely removing the nut. I did loosen it but i could not get any diesel up to it.

Sorry if as a complete newbie i've used any incorrect terms to describe my issue.

 

[jakeroyd]

I know you have already bled it but it's symptoms look very much like air in the system.
Bleed it progressively again working towards the injector.

 

[DoughMyDays]

I know you have already bled it but it's symptoms look very much like air in the system.
Bleed it progressively again working towards the injector.

Thanks Jake.

Is this nut a bleeding point that needs too be loosened also?

 

[Topcat47]

The bleed screw on my 1GM10 is actually by on the injector itself. (upper left in the picture). You don't seen to have the correct bleed screw if the picture is right. While not actually recommending this, a short term fix might be to try to bleed the injector through by loosening the return banjo on top of the injector.

When was the last time the injector and fuel pump were serviced?

 

[DoughMyDays]

The bleed screw on my 1GM10 is actually by on the injector itself. (upper left in the picture). You don't seen to have the correct bleed screw if the picture is right. While not actually recommending this, a short term fix might be to try to bleed the injector through by loosening the return banjo on top of the injector.

When was the last time the injector and fuel pump were serviced?

It is on mine too which i thought was weird when i looked at mine. Some things like this seem to be different.

I'm not sure when they were last serviced. The boat needed a bit of tlc before this and it's also been in a very bad accident due to the recent storms and it now tied to the jetty. The oil filter was changed early this year, but that's all I can see so far. ;(

 

[Topcat47]

I've seen worse engines that ran well. The 1 GM 10 has a pre-combustion chamber and the injector sits above a collar with holes in it that sits in the head. If the holes are clogged with soot, insuffiecient fuel will get into the cylinder. Another cause might be that the valves are not seating well and need to be lapped in, or the tappet clearances are too tight.

 

[Topcat47]

The correct sequence for bleeding the fuel lines are:- use the lift pump to bleed first to the fine filter mounted at the gears end of the head. Close that bleed screw when fuel comes out and then turn to the bleed screw at the injector pump. I'm lazy, so once fuel is up to the injector pump, I decompress the engine and use the starter motor to bleed though to the injector. As long as there's no leakages at any of the junctions, the engine should run.

 

[DownWest]

When was the last time the fuel filter was changed? Had the same symptoms with a Lister genset. The small AC filter on the engine was blocked.

Your circled connection is the high pressure connection to the injector. The last point to bleed. Though, as Topcat says, you can just spin her until you hear the injector working.

 

[Gixer]

When mine would run for a while and then cut out it was the fuel lift pump.

 

[Topcat47]

If the diaphragm on the fuel lift pump is split, you'll get fuel in the lub oil, although this isn't particularly common. The pump is cam operated when the engine is running and when stationary, you can tell if it's engaging by turning the engine over by degrees and operating the lever.

 

[DoughMyDays]

Thanks for all your feedback. Whatever we did.. It fixed the problem and was related to air and a change of a very dirty fuel filter.

Engine starts and runs first time not flawlessly