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Onan 20KW will not crank.


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  #1  
Old 08-12-2017, 08:24:06 PM
DN29626 DN29626 is offline
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Default Onan 20KW will not crank.

Model 30 ODEH 15R/5352D
Serial 0373604238
Onan with diesel Ford Industrial engine. Model 2712E
I am confident the starter went bad this summer so I had it rebuilt.
Currently the engine will not make a complete rotation. I know the battery is good.
I am considering the possibility that the engine is hydro locked.
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Last edited by DN29626; 08-13-2017 at 11:57:57 AM.
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Old 08-12-2017, 08:58:22 PM
YellowLister YellowLister is offline
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Default Re: Onan 20KW will not crank.

We need the full model and serial number of the generator to know what you have.

I would turn it over with a wrench first to see if it has any hard spots or maybe a stuck valve. Pull the valve cover and see if all the rockers move or maybe a push rod came off the lifter and the valve is not opening
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Old 08-12-2017, 08:58:29 PM
Wayne 440 Wayne 440 is online now
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Default Re: Onan 20KW will not crank.

Quote:
Originally Posted by DN29626 View Post
...Currently the engine will not make a complete rotation...I am considering the possibility that the engine is hydro locked...
IF that were my engine, any suspicion of hydrolock would be enough to justify measures to remedy same or determine the absence thereof. In other words, if it is hydrolocked you can break stuff easily, so make sure it isn't before you crank it anymore.
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Old 08-12-2017, 09:01:18 PM
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Billy J Shafer Billy J Shafer is offline
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Default Re: Onan 20KW will not crank.

I would remove the valve cover. Turn it by hand watch the valves one may be stuck.
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Old 08-12-2017, 09:04:06 PM
AngrySailor AngrySailor is offline
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Default Re: Onan 20KW will not crank.

Have you tried pulling the spark plugs?

Can you bar the engine over by hand? How is the oil level? Most times if hydraulic locked the sump level will rise from leakage past the rings. Maybe pull glow plugs if it has them. I hate to pull injectors if you don't have to, maybe you could unseat the exhaust valves by hand and bar it over watching for fluid. I would check for any other mechanical binding before getting out the BFH.
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Old 08-12-2017, 10:18:45 PM
DN29626 DN29626 is offline
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Default Re: Onan 20KW will not crank.

As much as I don't want to...
I guess I need to disassemble the factory enclosure so I can get to the top of the engine...and follow your advise.

Thanks guys. I hope to get this resolved without damage.
(Oh how I wish it did have glow plugs. The KISS system for relieving hydro lock.)
(I changed the oil during the spring, 2017)
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Old 08-12-2017, 11:17:31 PM
moteurdelco moteurdelco is offline
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Default Re: Onan 20KW will not crank.

These Ford are direct injection;if you think water is in the cylinders you can turn the exhaust rocker screws about 1 1/2 turn,this will act like a decompressor, and the engine will be able to rotate by hand. big screw holding the front pulley.
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Old 08-13-2017, 09:40:27 AM
Gunny Gunny is offline
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Default Re: Onan 20KW will not crank.

I now for sure you can get the valve cover off, even the head without pulling the housing apart.

Just the valve cover, leave the housing, if you have to pull the head, easier with the housing top off.

Just did this recently...........


Notices some bubbling going on at the head/block junction at the front. Pulled the valve cover and found a snapped off head bolt. Used a long left hand drill bit and a magnet and got it out. New head bolt and all was good. A co-worker (the not so bright one) took it upon himself to retorque the head. Still not sure why.
Torque specs are in Newton Meters, he went with foot pounds and wring off a few. Why he didn't stop with one I can't guess. Not real sure how he did it but he did get the head off with the housing intact. I put it back but pulled the top off so I could see what I was doing.
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Old 08-13-2017, 11:41:16 AM
DN29626 DN29626 is offline
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Default Re: Onan 20KW will not crank.

I have now placed the model and serial info in my post #1, as I should have when I started this thread.
Model 30 ODEH 15R/5352D
Serial 0373604238

Quote:
Originally Posted by moteurdelco View Post
...these Ford are direct injection...
...you can turn the exhaust rocker screws about 1 1/2 turn,this will act like a decompressor...
...big screw holding the front pulley...
Decompression.
Crankshaft pulley?
Do I turn with, or opposite of engines operating rotation?

( Gentlemen, Bare in mind, I don't know what has gone wrong, the symptom makes me think it is hydro locked. )
The engine and generator have operated trouble free until this summer, 2017.

Last edited by DN29626; 08-13-2017 at 12:02:34 PM.
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Old 08-13-2017, 11:53:55 AM
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Default Re: Onan 20KW will not crank.

Quote:
Originally Posted by DN29626 View Post
Decompression.
Crankshaft pulley?
Do I turn with, or opposite of engines operating rotation?

( Gentlemen, Bare in mind, I don't know what has gone wrong, the symptom makes me think it is hydro locked. )
The engine and generator have operated trouble free until this summer, 2017.
You can turn it either way. But best to go in order of rotation. I would go slow so as not to damage anything. If it has glow plugs I would remove them. For testing.
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