Onan Shutting Down

[Dan-sr@perra-us.net]

This is the same as the problem I had on my old Tiffin Allegro motorhome. The generator was a 4000-watt unit that did not have the generator enclosure found on more modern Onan generators. It was mounted behind the Left front tire. The problem manifested itself in two specific situations. First, on very hot days at highway speeds on the interstate the generator would occasionally stop. Fortunately, it would usually restart. The second situation was a little more of an issue because it would always cut out while I was driving uphill on long climbs to get over a pass in Colorado. After discussing the issue with several mechanics, we decided the problem was likely vapor lock caused by overheating due to the poor airflow at low speeds around the generator. Among other things the generator was designed to push the air toward the front tire, there was baffle the problem was that it would basically reregulate the hot air from the generator and suck up hot air from the main engine and the heat from the exhaust which was located below the generator fuel line. I ended up solving the problem by installing an electric radiator fan to blow cooler air into the generator compartment through the compartment door. Thor is not the only manufacturer that has this design issue. In retrospect I probably could have solved the problem by swapping the locations of the LP tank and the generator. Getting the generator away from the main engine probably would have corrected the problem. In fact, my Thor ACE 30.3 has the generator behind the LP tank on the driver's side much farther back from the main engine.