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Onan Generators

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.
Oops, the picture is upside down.
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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 offline
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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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Billy J Shafer Billy J Shafer is offline
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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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Old 08-13-2017, 05:05:04 PM
DN29626 DN29626 is offline
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Default Onan 20KW will not crank using starter.

I used a wrench on the crank shaft bolt and the engine turned ok, with resistance, but ok, as it should turn.
I believe this rules out hydro lock.
Put starter on again...same, weak, partial rotation results.
Again, I am suspicious of the starter because the engine has not run since before the starter rebuild.
For full disclosure, I had the rebuilder, recheck the starter last week and he insists it is right.
The starter is a Lucas M50. Now wondering if another starter is in my future as I am NOT convinced the starter is ok.

I will remove the valve cover and check valve movement before purchasing another starter.
PS I have added my Onan as my signature. If more info is needed for it, advise me please.
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Onan 20 KW 1 PH Generator
Lehman Ford 2712E Diesel Engine
Model 30 ODEH 15R/5352D
Serial 0373604238

Last edited by DN29626; 08-13-2017 at 09:08:14 PM.
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Old 08-13-2017, 05:21:48 PM
nothingbutdarts nothingbutdarts is offline
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Default Re: Onan 20KW will not crank.

Good clean connections from the battery to the starter?

Have you checked voltage drop from the battery to the starter and from starter to negative terminal?
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Old 08-13-2017, 05:24:57 PM
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Default Re: Onan 20KW will not crank.

LUCAS Knight of darkness.

Now you think it is the starter.

Well, you might want to try some simple things before doing a lot possibly unnecessary work.

Make sure the engine really is ok. Roll it a few turns by hand and feel for binding/ hard to turn.

Drain a little oil from crankcase.
Should be clear oil, no water or milky.
Look in radiator for oily film.

Put a voltmeter on the battery terminals. No load should be around 12.6.

Engage starter. I would expect over 9 volts at battery terminals. Anything less, battery not charged or defective.

Put meter on starter terminals. Engage starter. Should see less than 1 volt drop in cables. If not, R & R.

When you are sure everything is good, then you suspect knight of darkness.
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Old 08-13-2017, 09:23:42 PM
DN29626 DN29626 is offline
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Default Re: Onan 20KW will not crank.

Quote:
Originally Posted by Power View Post
...LUCAS Knight of darkness...
I am not sure what that means.
Quote:
Originally Posted by Power View Post
...Now you think it is the starter...
Before I posted here, this was my original suspicion, and that's the reason I went back to the rebuilder.
(I had the rebuilder, recheck the starter last week and he insists it is right.)
Quote:
Originally Posted by Power View Post
...Make sure the engine really is ok. Roll it a few turns by hand and feel for binding/ hard to turn..
I turned it by hand several rounds.

---------- Post added at 09:23:42 PM ---------- Previous post was at 09:19:51 PM ----------

[/COLOR]
Quote:
Originally Posted by nothingbutdarts View Post
...Good clean connections from the battery to the starter?
I cleaned both ends of both cables as well as the battery. The cables are less than a year old. I replace cables when they become unsightly.

Quote:
Originally Posted by nothingbutdarts View Post
...Have you checked voltage drop from the battery to the starter and from starter to negative terminal?
I have not. I will do this next.
I did replaced the battery with another known good battery. I did check both batteries, both are good.
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Onan 20 KW 1 PH Generator
Lehman Ford 2712E Diesel Engine
Model 30 ODEH 15R/5352D
Serial 0373604238

Last edited by DN29626; 08-14-2017 at 06:13:36 AM.
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Old 08-13-2017, 09:38:14 PM
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Default Re: Onan 20KW will not crank.

Lucas knight of darkness is an old saying about electrical parts made in England. They were famous for quitting and working again. I had a friend that had an XKE jag. Dash would be working fine then go out then come back on. Or half the dash would go out then come back. Never could get them to work all the time.
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Old 08-13-2017, 09:38:34 PM
Wayne 440 Wayne 440 is offline
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Default Re: Onan 20KW will not crank.

Quote:
Originally Posted by Power View Post
LUCAS Knight of darkness...
Quote:
Originally Posted by DN29626 View Post
I am not sure what that means...
Lucas electrics are infamous as a source of mysterious, intermittent, frustrating problems.

http://www4.ncsu.edu/~mtmorris/index3.html
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Old 08-13-2017, 09:58:56 PM
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Default Re: Onan 20KW will not crank.

This is for a 2711E 30KW DEH. Which is what enine is listed as used in the DEH But this the original part number. For a 69/75 engine
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Last edited by Billy J Shafer; 08-13-2017 at 10:10:19 PM.
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Old 08-13-2017, 10:07:12 PM
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Default Re: Onan 20KW will not crank.

Quote:
Originally Posted by Wayne 440 View Post
Lucas electrics are infamous as a source of mysterious, intermittent, frustrating problems.

http://www4.ncsu.edu/~mtmorris/index3.html
I didn't see the one about the Lucas rubber adjustment hammer.
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Old 08-14-2017, 08:10:14 AM
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Default Re: Onan 20KW will not crank.

They drink warm beer in England because they have Lucas refrigerators,

Bob
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Old 08-14-2017, 12:02:19 PM
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Default Re: Onan 20KW will not crank.

Having owned & worked on British cars, I can say a few things.
Generator -a generous 24 amps. If headlamps are on and you turn on anything else, battery discharges, leaving you stranded.

All in one voltage regulator- 1 relay does it all. As set from factory, when lights and accessories are off, boils electrolyte out of battery. If you lower setting, with lights on, battery discharges.

Use of a horn relays for headlight relays. I got about an hour from dealer on LIE, and it burned out, extinguishing headlights.

Undersized wires and oversized fuses. #20 wire protected by a 35 amp fuse. When wire overheats, it shorts out entire harness.

Grounds? waste of copper. 1 #18 should be fine on a fiber glass bodied car--- until you turn on more than one thing.

Solder connections- cold solder joints are best, take longer to overheat.

Dodgy bullet connectors. Make sure to put them where they get wet, helps keep them cool.
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