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.
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What to Check and How
Hi Anthony, Based on your observations the engine is either not getting air or has restricted exhaust. You said you removed air filter and saw foam was gone. Need to be sure the intake manifold is not blocked. Remove the filter completely, check intake manifold to be sure it is not blocked and try to start w/o air cleaner. If problem persists remove the exhaust elbow at the engine and make sure the exhaust port is open. Try to start with exhaust manifold not connected. This will put a bit of smoke / exhaust in the boat - but you will only crank until start - then shut down. If it starts with the exhaust manifold not connected then the manifold or exhaust is plugged. Think that's where you will find the problem since the engine is >15 years. Good Luck, Bob
Hi Anthony, Based on your observations the engine is either not getting air or has restricted exhaust. You said you removed air filter and saw foam was gone. Need to be sure the intake manifold is not blocked. Remove the filter completely, check intake manifold to be sure it is not blocked and try to start w/o air cleaner. If problem persists remove the exhaust elbow at the engine and make sure the exhaust port is open. Try to start with exhaust manifold not connected. This will put a bit of smoke / exhaust in the boat - but you will only crank until start - then shut down. If it starts with the exhaust manifold not connected then the manifold or exhaust is plugged. Think that's where you will find the problem since the engine is >15 years. Good Luck, Bob
Agree with Bob
It definitely could be the mixing elbow, but his ingenious test for it is done easier by visual inspection. If the openings are coked up with rust and soot to the point they are sealed shut, you need a new mixing elbow. They're only good for 3-5 years, so this could be it. The Archives have instructions and photos. In sum, the engine simply can't breathe, so it can't start.
It definitely could be the mixing elbow, but his ingenious test for it is done easier by visual inspection. If the openings are coked up with rust and soot to the point they are sealed shut, you need a new mixing elbow. They're only good for 3-5 years, so this could be it. The Archives have instructions and photos. In sum, the engine simply can't breathe, so it can't start.
Without Exhaust Manifold!!!
For those who have never tried running and engine without the exhaust manifold please be aware that there will be long tongues of naked flame and the noise will be incredible. The likelihood of inlet or exhaust manifolds being blocked seems remote as the suction is great enough to draw in and munch up any foam which may have come from the filter and, as it was running at high revs previously, there doesn't seem much wrong with the exhaust. The gas flow at idle would be much less than was required for 3000 rpm. It would seem more like a compression or fuel problem. You need a compression test to verify piston rings not broken or stuck it their grooves, no hole in piston crown, head gasket not blown, valves OK, con rod not bent. Also try removing the injector, reconnect it to the fuel line and hand crank the engine - then the fuel should come in a fine spray every second rev of the engine. Its an old guy so you might get it going with 'damp start', ether or WD40 and I doubt you would cause damage BUT the problem will still remain so it needs sorting anyway. Running without the manifold in the confined and highly inflammable space of an engine compartment, even for a couple of seconds, really is living dangerously. Good luck.
For those who have never tried running and engine without the exhaust manifold please be aware that there will be long tongues of naked flame and the noise will be incredible. The likelihood of inlet or exhaust manifolds being blocked seems remote as the suction is great enough to draw in and munch up any foam which may have come from the filter and, as it was running at high revs previously, there doesn't seem much wrong with the exhaust. The gas flow at idle would be much less than was required for 3000 rpm. It would seem more like a compression or fuel problem. You need a compression test to verify piston rings not broken or stuck it their grooves, no hole in piston crown, head gasket not blown, valves OK, con rod not bent. Also try removing the injector, reconnect it to the fuel line and hand crank the engine - then the fuel should come in a fine spray every second rev of the engine. Its an old guy so you might get it going with 'damp start', ether or WD40 and I doubt you would cause damage BUT the problem will still remain so it needs sorting anyway. Running without the manifold in the confined and highly inflammable space of an engine compartment, even for a couple of seconds, really is living dangerously. Good luck.
Athrosclerosos??
Anthony, We had a very similar if not exact same problem with the same engine in our Wilderness 30. It turned out that the exhaust manifold had a bad case of athrosclerosis. Carbon deposits had reduced the diameter of the exhaust by about 80% and the boat began to suffer major iron heart failure. A simple angioplasty corrected the problem and we were back to normal activity again !!!
Anthony, We had a very similar if not exact same problem with the same engine in our Wilderness 30. It turned out that the exhaust manifold had a bad case of athrosclerosis. Carbon deposits had reduced the diameter of the exhaust by about 80% and the boat began to suffer major iron heart failure. A simple angioplasty corrected the problem and we were back to normal activity again !!!
more info
-----Original Message----- From: Anthony Bavuso Sent: Monday, December 02, 2002 11:14 AM Subject: RE: Problems with yanmar 1GM10 Hi 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.
-----Original Message----- From: Anthony Bavuso Sent: Monday, December 02, 2002 11:14 AM Subject: RE: Problems with yanmar 1GM10 Hi 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.
Care Needed
Anthony, If you have fuel in the lube oil I suggest you do not try to start the engine. It is not unknown for a diesel to run on its sump oil if it has been overfilled. If the reason for higher than normal oil level is fuel then this will make it much more likely to run away. Should this happen the engine does not respond to the throttle nor to the stop lever. It just builds up revving higher and higher as the oil becomes more stirred up until eventually there is a mechanical failure somewhere. The only way to stop the engine under these conditions is to put your hand over the air intake and starve it of air. You might not want to do this if the thing is revving really fast. Lastly diesel is not a good lubricant for bearings so this is undesirable too.
Anthony, If you have fuel in the lube oil I suggest you do not try to start the engine. It is not unknown for a diesel to run on its sump oil if it has been overfilled. If the reason for higher than normal oil level is fuel then this will make it much more likely to run away. Should this happen the engine does not respond to the throttle nor to the stop lever. It just builds up revving higher and higher as the oil becomes more stirred up until eventually there is a mechanical failure somewhere. The only way to stop the engine under these conditions is to put your hand over the air intake and starve it of air. You might not want to do this if the thing is revving really fast. Lastly diesel is not a good lubricant for bearings so this is undesirable too.
Has the injector been tested yet?
Anthony: Has the injector been test yet? If your oil level is increasing and you are getting fuel to the injector I would think that you have fuel leaking down the cylinder walls and filling the crankcase. You may want to get that injector check and be sure to get a new installtion kit so the injector is properly sealed. Before you run the engine, you will want to change the oil too. I think you also need to remove the elbow and inspect it too. Without checking this you will NOT know if your engine will even breath. Once you remove the elbow you will either need to replace the elbow or just reinstall the elbow with a new gasket. The only other word of warning, if you are going to continue to crank this engine you may want to shut off the raw water intake. You can flood your cylinder with water backing up from the muffler.
Anthony: Has the injector been test yet? If your oil level is increasing and you are getting fuel to the injector I would think that you have fuel leaking down the cylinder walls and filling the crankcase. You may want to get that injector check and be sure to get a new installtion kit so the injector is properly sealed. Before you run the engine, you will want to change the oil too. I think you also need to remove the elbow and inspect it too. Without checking this you will NOT know if your engine will even breath. Once you remove the elbow you will either need to replace the elbow or just reinstall the elbow with a new gasket. The only other word of warning, if you are going to continue to crank this engine you may want to shut off the raw water intake. You can flood your cylinder with water backing up from the muffler.
Stoping Runaway Engine & Water in Engine
I'd second Don Alexander's caution about watching out for a runaway engine. There's a lot of mass and intertia in all those moving parts and to stop them will cause a good suction. Rather than putting a hand over the air intake I'd feel much more comfortable with something like a shoe, at least not a body part ;-). Water in Engine: If you're having a hard time starting the engine you don't want to crank it too much at one time as it'll suck water in through the exhaust and then you'll have a real mess. The Yanmar manual say you can crank it for a certain length of time (2 minutes??? - read the manual) and then you have to let it rest(time=??).
I'd second Don Alexander's caution about watching out for a runaway engine. There's a lot of mass and intertia in all those moving parts and to stop them will cause a good suction. Rather than putting a hand over the air intake I'd feel much more comfortable with something like a shoe, at least not a body part ;-). Water in Engine: If you're having a hard time starting the engine you don't want to crank it too much at one time as it'll suck water in through the exhaust and then you'll have a real mess. The Yanmar manual say you can crank it for a certain length of time (2 minutes??? - read the manual) and then you have to let it rest(time=??).
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