rlbarkleyii

Onan LPG Gen Set wont start, HELP, HELP!

10 posts in this topic

Changed the oil and filter on my Onan Mobile Genset HGJAB (MARQUIS) , 6500 kw (333 hours) high pressure propane fueled. Ran like a bandit one hour before oil change, now the darn thing wont start at all? Two thirds tank of LPN.

To change oil I opened the access panel, opened the LPG oil drain ****, opened the engine oil **** drained oil. CLOSED both petcocks.

Removed and replaced the oil filter with new one. Filled the filter core with oil before installing, refilled with 15W-40 DELO and checked the oil level.

Oil level 1/3 up the stick from add. Not overfilled, not underfilled. Tried to crank it up, turns over fast, but non hits or misfires, just would not start, smelled fuel, no ignition?, no fuel?

What did I do wrong??? HELP, HELP, HELP!!

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Some Onan generators have a sensor in the oil sump that will shut down the generator if the oil level is low.

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Thank you for your reply. I am aware of the oil shutdown sysytem. I had the oil level initially filled to the full level, and when it wouldn't start i wondered if i had overfilled it and removed some of the oil to about a little below half full. Tried several more times, no go!

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Do you see a vent hose underneath the unit? This is a vent and it may be plugged. Run a wire into it to unclog it and try again.

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I had to look at the oil requirements when you mentioned 15-40 grade and it is OK for the unit.

Regarding the oil filter, the manual lists part number 122-0836 for your unit. Was the proper filer used ? Part number 122-0800 is listed for a number of the generators.

You mentioned smelling fuel, so that should not be an issue unless there is an open fuel line.

With no hits or misses, it sure sounds like ignition issue, the only thing I question is an oil filter issue ??? But if that part number is correct, that leaves ignition or that open fuel line I mentioned.

Do you read any codes from the System? What year is your coach?

Rich.

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With a propane generator, it is easy to rule out fuel as the cause (meaning the issue is ignition-related.

Shut off the coach main 120 VAC breaker.

Get a propane bottle/torch-- do NOT light it.

Turn on propane with the nozzle of the torch in the air cleaner.

If it tries to start, you have a fuel issue. If not, an ignition issue.

You could also pull a spark plug wire and see if you have fire, but in many installations, the spark plugs are difficult to access.

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Is it possible you have an air bubble on the oil sensor giving it a false reading of low oil? Try agitating the unit to get rid of any bubbles, and possibly removing and reinstalling the sensor.

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You might try looking at your leak detector in the coach, if it smells propane it will shut off the flow until it resets and you can verify if you have propane flow by lighting a stove top burner. If it lights you have good flow and you will have to look elsewhere.

I had a similar problem with my coach. I couldn't get anything to light and I noticed that some one had turned off my leak detector.

Good luck.

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Thanks to all who replied.

Repair completed genset now operating ! LESSON LEARNED: Engine would not start because hose from bottom of carburetor to crankcase behine the drain valve had deteriorated due to the use of a non-approved type rubber hose which disintegrated . I must have touched it when changing the oil, and it crumpled without my knowledge. Replaced the hose and it now runs great.

Cummins Parts # Hose. 503-2143-01

Clamps. 503-1951-20
Do not use other than Cummins OEM parts for this repair. Approximate cost of parts $40.00 including shipping.

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