Yanmar 1GM10 wont start

[Anthony Bavuso]

I am having trouble with diesel my engine. Below is a copy of the email I sent to my mechanic. Does anyone out there have any suggestions?Markus,Greg over at Yacht Haven pointed me your way about problems I am having with my Yanmar 1GM10. The engine was installed in 1985 into a Hunter 25.5. Here is the scenario, a few days ago I went to start the engine and she was harder to start than normal. Once she started there was more smoke out of the exhaust than normal. Not a huge amount of smoke, just more that I had seen in the past. She was more sluggish on the throttle than normal. I had attribute all of the symptoms so far to the cold weather. But after running her for an hour or so a 3000 rpms I notice she had dropped to 2700 rpms. I went to adjust the throttle and put it back to idle and the engine quite. It hasn't started since.I took off the air intake cover and notice that the foam element material was pretty much gone. I assume the material was sucked into the intake manifold.I replaced the fuel filters, and bead the air out at the filter, at the injector pump and at the injector. Still she won't start. Every now and then she will pop and once she popped a few times but once you let off on the starter she quits.One thing I noticed that I thought was odd. When bleeding the injector I backed off the high pressure line nut at the injector a turn and turned the engine over with the started. And fuel dripped out from around the nut. I had expected seeing fuel spray out at high pressure. Is it supposed to drip? or spray out?Greg suggested pulling out the injector and bringing it over to you guys to test it. What do you recommend?Thanks for your help.

 

[Dave Weir]

1GM10Starting

Anthony,Sounds like the high pressure pump (especially if you get fuel at the bleeder on the low pressure/input side of the pump). Fuel should spray when you loosen the nut. Definitely don't pull the injector until you have ruled out the pump.Dave WeirLast Resort

 

[Miles]

If you really sucked the filter in...

you've got a real problem. You mention that the filter element is missing pieces and you think they may have been sucked into the intake manifold. If true you've got a real mess on your hands.When I bleed the pipes at the injectors the oil sort of dribbles out but it would depend on how far you back the nuts off.I wouldn't mess with the injector until you've ruled out some other things like the disappearing filter... Good Luck!

 

[Anthony Bavuso]

so more info

-----Original Message-----From: Anthony Bavuso Sent: Monday, December 02, 2002 11:14 AMSubject: RE: Problems with yanmar 1GM10Hi Markus,Well I was able over the holiday to do some of the trouble shooting that you had suggested on the phone. Based on your test of putting the palm of my hand over the intake, and trying to pull if off while running the starter... seems to me to be sufficient suction.Also while hand cranking the engine over we listened with a stethoscope for the atomizing sound from the injector and I wasn't sure it was making the noise. But after hand cranking it a few times while listening we started hearing a spring like sound coming from the injector near the point in the stroke where you could feel the compression on the hand crank. It looked like the sound was coming from the injector and the sound was traveling through the high pressure fuel line coming from the injector pump. The fuel line was vibrating near the injector. We had not previously hear this spring like noise.I removed the exhaust mixing elbow and did not see any blockage. Although I did stick my finger in the block and noticed a black liquid substances all inside the exhaust port. It looked to me like lube oil? How is lube oil getting into the cylinder?The last piece of telling information is that measured by the dipstick the oil level in the sump is rising. And the oil on the dipstick seemed thinner and more runny. I didn't see any of the signs of water in the oil, so I would assume that the extra fluid in the oil sump is fuel.My manual says the first place to look if you have fuel in your oil is the lift pump. But I can exercise the priming lever on the lift pump and fuel squirts out at normal flow from both the fuel filter bleed and the injector pump bleed.So our working theory about the fuel in the oil which I hope you can confirm or dispute is that we cranking an engine that is cold since the piston is a little smaller due to the temperature that you get some blow by between the cylinder and the piston, now the theory is that once the engine heats up the piston expands closing the gap and no more blow by. This theory would seems to explain how fuel is getting into the lube oil and how lube oil is getting in the exhaust by way of the combustion chamber.Thanks so much for all your help.