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vsheetz · 02-22-2021, 07:17 PM

I had a 5500 in a previous coach. Would stall/stop with motion (ran perfectly if stationary) - unless the oil level was right up to the very tippy top.

GypsyR · 02-23-2021, 08:55 AM

I can totally see an overly sensitive oil level sensor causing it.

RV8411 · 02-23-2021, 12:19 PM

Thank you for all the suggestions and that made me think more about the issue.

The generator is 10 years old mounted on a Ford F53 chassis. The float flooded 2 years ago and I replaced the carburetor with a cheep knock off. The problem may have started earlier as it occasionally stopped with the old carb but I blamed the float.

The float theory is interesting but a bad float level will change the mixture. When I installed the new carburetor I measured voltage and frequency as I adjusted the linkages to handle 0 to 100% load without stalling. You would think a large load change = fuel change would be similar to going over a bump. The F53 chassis is a hard ride and normal driving over bumpy roads does not cause a problem.

Low oil could be an issue but I normally drive with it full and no issues up and down steep hills or cornering.

The generator can be started immediately with no issues so a bad ground is unlightly.

My best guess now is a loose wire or cracked circuit board but how to test as only severe bumps effect it. The wiring diagrams show all the sensors and switches going into the circuit board and nothing daisy chained so the board logic determines when to close the fuel cut-off solenoid. I plan to tug some wires while the generator is running and hit the base with a rubber mallet to try to induce a failure. After that I will try to check the connections to the circuit board and if I can look for cracks in it.

Did I miss anything?

Unplanned Tourist · 02-23-2021, 04:56 PM

Also look for any place the wires to one of your start/stop switches could be rubbed, or pinched.

I'm not certain, but I think the signal to shut off from any switch is just a grounding of the wire. So if there's a place where the wire is touching any bare metal, that would shut it down.

RV8411 · 03-02-2021, 09:23 AM

So a suggestion was low oil level. Looking at the wiring diagram there is no oil level sensor but there is a low oil pressure switch. If that opens you get a fault code # 2 which I have never scene so I am discounting that cause.

I ran the generator and disturbed the wiring to no effect. Then I hit the unit hard with a rubber mallet and still no effect.

I found a small movement of the arm connected to the governor and controlling the carb throttle caused either an under voltage #13 or under frequency #15 error. Looking at the wiring that I reconnected to the new carburetor it was very close to the arm and may have interfered with movement. I zip tied it away and will be going on a trip in 2 weeks on roads I know have caused a problem.

Will keep you updated.

RV8411 · 04-07-2021, 07:12 AM

Success. Just returned from a trip and the generator did not fail even once. Looks like tying the wiring loom back to prevent possible interference with the speed regulator arm worked.

Thank you all for your suggestions as it helped me eliminate other causes I had not thought of. I was about to replace my $50 carburetor with an Onan $350 carb but you inspired me to try harder in diagnosing the problem.