Lazy Daze Owners' Group

Generator shut down only while driving.....Fixed.

June 03, 2021, 12:18:48 am

2006 Mid Bath, Onan MicroQuiet 4000. Searched all the forums, considered lots of common problems from fuel lines to fuel pump. After lots of searching, I saw a post about the generator fighting for fuel with a faulty gas cap. I remembered my gas cap making noise when my engine was running. On a whim, I spent $17 for a cap at Oreilly. Problem solved! Generator would run all day in driveway, but after starting the engine, it would quit in 10-20 minutes. Now, runs indefinitely while driving.
Hopefully this might help someone with the same problem.

Re: Generator shut down only while driving.....Fixed.

Reply #2 – June 03, 2021, 01:32:58 pm

I cannot imagine how changing a leaky gas cap fixed the generator's problem and would expect the problem to return.
Any suggestions of how this worked?

Modern gas caps are sealed, venting air to the gas tank is provided through the evaporative emissions system's carbon canister, located near the fuel tank. The carbon canister absorbs and retains any escaping fuel vapors, to be burned later when the engine is running.
If the engine still runs without problems, the carbon canister isn't blocked or the engine would eventually run out of fuel when the engine's fuel pump could not overcome the tank's increasing vacuum.

Larry