Onan Generator shuts off

[wrayrichards]

I have an Onan Marquis 7000 in my 34' National.  The generator runs perfect while in the yard or at the repair shop, however after driving approximately 40 miles the generator shuts off.  If it restarts it only runs for a few minutes.  It has been serviced, fuel pump replaced, fuel filter replaced, and tuned up.  Has anyone experienced this issue and if so what might be the solution?
Thank you,
Ray

 

[ArubaBound2011]

What was the temperature at, i noticed when it gets in the 90's you have to keep the door open on the generator compartment especially when in that heat sitting in traffic, mine did the same thing at a Rv park when it was hot after i opened the door it would stay on. they are air cooled, hope that helps

 

[darsben]

One possible solution is moving the fuel pump away from the generator. Some pumps were getting to hot and vapor locking the motor. Moving the fuel pump cured the problem. Others have had to cut additional louvers in the compartment door to increase air circulation

 

[Gary RV_Wizard]

Does it work again after arriving at your destination?  If the problem occurs only while driving, I suspect the issue is one of these:

1. Heat build-up causing an auto-shutdown by the genset controller
2. Heat build-up causing vaporizing the fuel in the line or pump
3. Inadequate air intake while underway (airflow over the RV disrupts flow into the genset cabinet)
4. Fuel supply from the RV tank while in motion (sloshing fuel, tank vent, etc).5. Oil sloshing in the genset pan causes an intermittent low oil condition, resulting in a shutdown