After I changed the oil in my '79 H33 this weekend I started up the Yamar 2QM15 to get the fresh oil worked through. After running at low rpms for a few minutes in neutral I throttled up. She had never purred so soundly before. Then the engine took-off on its own and revved out of control. I backed the throttle off, turned the key off, and shut off the fuel line... all to no avail. White smoke billowed as there was obviously enough fuel remaining in the system. I quickly darted below and held my hand over the air intake. After a minute or so the engine finally stopped. I started her up again a few minutes later and all appeared fine. Anyone have any idea what the heck happened??? -Marvin Baltimore
Engine stuck at high RPM
- Thread starter mjmulleriii
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Too much oil...
If you don't keep track of how much oil you take out, and then put that much back in, you can easily overfill the oil pan. Diesels will use that to run on, and since you shut off the fuel, it sounds likely that it was burning excess oil. Check your dipstick before you start it up again... That's my guess. Steve
If you don't keep track of how much oil you take out, and then put that much back in, you can easily overfill the oil pan. Diesels will use that to run on, and since you shut off the fuel, it sounds likely that it was burning excess oil. Check your dipstick before you start it up again... That's my guess. Steve
oil on top of pistons
You somehow got oil on top of your pistons and had a runaway. Either you have some valveguide seals going bad letting the oil leak in from there. overfull of oil, or possible ring damage. have heard of it before but have never had it happen to me. Tim Welsh, H34 AKA Cabo Wabo
You somehow got oil on top of your pistons and had a runaway. Either you have some valveguide seals going bad letting the oil leak in from there. overfull of oil, or possible ring damage. have heard of it before but have never had it happen to me. Tim Welsh, H34 AKA Cabo Wabo
I'll go with overfill too.
I also think that you had an overfill situation. This caused too much pressure in the crankcase and the oil went UP into your cylinders (runaway engine syndrome). This can happen when some boats are motorsailing too (heald over) and the engine starts sucking crankcase oil. You did exactly the right thing but I do not know if your hand was the correct choice. They only practical way to shut it down is to starve it from air. Using the de-compression lever is a no-no according to the service manual. But I would do that if the air thing did not work.
I also think that you had an overfill situation. This caused too much pressure in the crankcase and the oil went UP into your cylinders (runaway engine syndrome). This can happen when some boats are motorsailing too (heald over) and the engine starts sucking crankcase oil. You did exactly the right thing but I do not know if your hand was the correct choice. They only practical way to shut it down is to starve it from air. Using the de-compression lever is a no-no according to the service manual. But I would do that if the air thing did not work.
What oil do you use
I've heard every possible answer. A diesel mechanic told me 30W was proper. My yard man said 15x40 was a must. I ended-up using 30W. Could that have been a factor? And if so, why?
I've heard every possible answer. A diesel mechanic told me 30W was proper. My yard man said 15x40 was a must. I ended-up using 30W. Could that have been a factor? And if so, why?
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