Lance onboard Onan running issues

It might have something to do with water in the propane tank getting into the regulator and freezing or generally causing havoc. When I have this (IMHO) issue with the Onan upon quickly checking the regulator, it indicates an out of propane condition (red) even thought there is half a tank. See this article for more info.

Why a regulator freezes up

Partial extract:
"If all LP-gas regulators have to do is reduce a high pressure to a lower pressure, why do they freeze up? The short answer is “water”, but, as you know, nothing is ever quite that simple.
To keep your customer warm and happy, day after day, year after year, your regulator has to do some pretty tricky things. It’s got to baby the pilot light, rise to the occasion every time the furnace kicks on and shut off completely when it’s supposed to..."

Mine started acting up on those really hot days we had back on July 4th weekend on the island,it started to act up about an hour in and was really bogging when the compressor kicked on, I think it was overheating. I ended up shutting it off and leaving early that weekend. Now that I think back the little bit of wind that was there had shifted from S to N and was blowing at the front of the truck so that probably did not help the situation but it did help keep my truck cooler on the drive back to the air pumps.

I prepped my camper for the same reason, thank goodness we didn't have to use it. But my onan fired right up and it was raining out so I don't really have an answer to the humidity question. Maybe yours is running lean or has a port partially blocked?

That’s a good possibility. I’ve had both the built in Generac on my TC and my home standby generator shutdown due to overtemp. Both are air cooled, and the overtemp sensor on both is set to about 192 degrees IIRC. The normal engine running temperature is only about 10 degrees below that on my standby generator.

If we have a power outage at home when the ambient temps are above 95 or so, I have to open the sound deadening enclosure up to help cool it. I’ve never measured the temperature on the TC generator, but it shut down once at Arches NP when it was about 100 degrees.

:):)

90 degrees maybe it just got to hot in that compartment they,ve been known to melt the compartment door. Maybe you could try putting a small fan underneath blowing up with the door opened.

Propane is a by-product of gasoline refinement. I had a problem where the propane continued to 'refine' in the lines. Ended up with oil in the propane lines, and of course, the generator is the low spot in the system. Blew all the lines out, but the generator was never quite the same afterward. Put in a T-trap with a dead stub that I drain a few drops of oil out every year or two.

HTH,
-Eric

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The LP fuel supply to your generator is fairly straightforward. The LP pressure is regulated by the regulator at the LP tanks, so you should rule out any problems with it before digging into the generator too much. It should be a minimum of 11” water column on a manometer. It will normally be adjusted a little higher than that so that when all your LP appliances are running, you still have 11”.

After the LP goes through the campers regulator, it then goes to the lock-off solenoid on the generator. That solenoid is controlled by the gen-set, but you should be able to easily determine if it’s energized and open or not with a test light. If the lock-off solenoid is opening, the LP then goes to a device that looks like another LP pressure regulator. It’s called a zero-governor regulator, and it’s purpose is to only let LP flow to the carburetor on the engine if there is vacuum in the intake manifold, like when the engine is either cranking or running. The size of the diaphragm in the zero-governor makes it very sensitive to vacuum, and it should open on its own when there is even the slightest vacuum in the intake.

The diaphragm in the zero-governor can get pin holes in them which makes them less sensitive to vacuum, and the little valve inside the governor can stick closed. Both issues can make the generator hard to start. If you end up replacing the zero-governor, try to find one that has a manual prime button on it so you can force it open when needed. It makes the generator easier to start if you can prime it before cranking, and it makes troubleshooting a problem like this easier.

I think it’s less likely the zero-governor was the cause of the first shutdown/unable to restart incident. That sounds more like the gen set overheated, had low oil pressure, or one of the sensors that detect those conditions is failing. I’ve had to replace one or both of those sensors on the built in Generac in my TC, and the standby generator on my house. If you can get to those sensors and unplug them the next time it won’t start, that may help isolate the problem. If the generator starts, the sensor is bad.

:):)

I have had some similar experiences with mine. Error light indicated service generator. Mine had 10 hours on it when this started.

Anyway I think it has something to do with the propane supply. Possibly something to do with the propane tank safety float or a regulator problem because I notice when this happens, the regulator shows "red" like the tank is empty but it is over 50% full. Still troubleshooting but do not think it is the generator.