I'm convinced mine was from heat
It would die, often when driving...but sometimes in a parking lot...usually after being driven &/or in the very hot sun.
I made my own vent using a louver from West marine....
I can't believe that I can't find a photo of the finished product.... but here's one of my first attempt. I was just trying to supplement the air with some cooler air form outside, so I wasn't overly concerned that it's smaller than the generator's intake
With just the louver, it wasn't enough.
It pulled in some cooling air, but was still pulling in most of its air from behind the door.
I ended up buying a second louver, and cutting and splicing the two together to make a rectangular louver....imagine one above the other except take away the middle sets of screws. If you look close you can see my seem but you have to look close. the louvers just continue their spacing and it was the perfect size to match up to the onan's intake holes.
Then, I fabricated a little baffle using some silicone rubber engine baffle material (like this https://www.aircraftsupply.com/tsr-3-1-8.html
and some aluminum angle. pop riveted it to the
No reason though I think to use the specialized rubber, any old rubber...say from an old mud flap...would do.
The other thing I did, was to insulate my fuel line feeding the genny. I found that Thor had just draped it loosely in the slipstream under the MH, surprisingly near the driveshaft. I insulated the hose with regular pipe insulation form the hardware store, and tucked it much more neatly and more securely up against the frame (further away from teh V-10 exhaust system)
At the same time, I changed the oil and fuel filter.
After approx 5,200 miles through the high desert this summer, I'm fairly confident then this effort worked.
I was prepared to try one or both of two other ideas found in research
....add a second fuel pump to the line, but back close to the gas tank
.... add in a return loop at the generator's carburetor back to the tank so that more fuel would flow
But I don't think either of these will be necessary in my case.