Onan propane generator not starting

[jdog]

Onan model # 3.6KYFA2612OL propane generator will not start. Has new spark plug and air filter. Does not seem to have oil pressure sensor. Propane tank is a little under 1/2. Vent. tube is not plugged. I did get it to start by spraying carb cleaner in the air intake with the air filter off. It ran as it should. Kept running until I shut it off. Would not restart without cleaner. What would this indicate? Any help will apprecieated. It is in a 2007 Gulfstream Class C motorhome.

[jdog]

I think I will take it to the Cummins/Onan shop and have the propane system checked. The propane system is not what I want to mess with!

[MrWizard]

jdog wrote:
Onan model # 3.6KYFA2612OL propane generator will not start. Has new spark plug and air filter. Does not seem to have oil pressure sensor. Fuel tank is a little under 1/2. Vent. tube is not plugged. I did get it to start by spraying carb cleaner in the carburetor with the air filter off. It ran as it should. Kept running until I shut it off. Would not restart without cleaner. What would this indicate? Any help will apprecieated. It is in a 2007 Gulfstream Class C motorhome.

fuel tank ? do you mean your propane tank ?

how do you spray carb cleaner into a Propane system ?

spray it into the air filter

IF you have a propane Onan, and the genny won't run, then you have a propane feed problem, mine is LIquid feed, not gaseous
my propane tank HAS (2) valves, one down low for liquid to the Onan
that valve must be OPEN for my Onan to run

[SquirrelyM]

jdog, I recently had a similar problem with the same generator model as yours. It would crank fine but not start. After checking all of the simple things, I gave up and took it to the Cummins shop in San Leandro.

I hovered nearby so that I could see what he was doing. He didn't seem to mind. Here's what he tried:

* Removed the vent hose at the top of the engine, blew through it, tried to start with the hose disconnected (no luck)
* Verified that the fuel solenoid was clicking when depressing the Stop/Prime button
* Used a meter to check the solenoid lead
* Disconnected the generator from the RV propane supply and connected his own tank with regulator (no luck)
* Removed the spark plug and checked the gap spacing
* Disconnected the internal fuel hose and tested the gas pressure when the solenoid is active (pressure was good)
* Removed the valve cover and checked the springs and spacing
* Removed the control module (solenoid switch is mounted to the top of the module), disconnected the wire bundle from the underside of the module, checked a couple of pins in the bundle with a meter

After reinstalling the spark plug and valve cover, reconnecting the fuel hose and the wire bundle, it started right up. If it hadn't, his next test would have been to bypass the generator's fuel regulator. If it was a problem with the regulator, it would have meant pulling the whole generator out. Fortunately that wasn't necessary.

His best guess is the culprit was the wire bundle. He noticed some pins that looked out of place and he spent some time adjusting them.

I have a 2007 Gulfstream Vista Cruiser Mini.

Hope it helps!

[jdog]

Thanks, I will check the mixer gasket to the head for leaks and then report back. I don't think there is a fuel to air adjustment on propane generators.

[Generator_Jim]

Had a problem with the gas version of this unit. Turned out to be one of the gaskets between the carb and the cylinder head. Bolts were loose due to vibration and caused vacuum leak preventing adequate fuel mixture for starting.

If very high hours on unit and liquid withdrawal, check if oil is interfering with the fuel solenoid. Propane can precipitate oil out at the point of vaporization.

JimL

[TEXAS]

Try adjusting the fuel mixture screw.