CLASS RACER FORUM - View Single Post - Onan 4000 with shut down but will restart

Rich Biebel · 07-02-2020, 06:10 PM

Make sure the oil is not too full. It can be in the middle of the dipstick good area.

Most of the new machines are set a touch lean on the carbs mixture. For best CO Emissions....

You could try richening it up 1/2 a turn, out..

The black plastic cap on the carb is a tamper proof item that prevents you from backing that mixture screw out past where it was set at the factory. It allows just a small amount of change for altitude....leaner....

The black plastic cap is knurled and so is the mixture screw. It just presses on. You can very carefully with a bent screwdriver pry that cap off. Carefully because the mixture screw is brass and can be broken. It's a needle inside....

Richen it 1/2 a turn out from it's most rich setting and see if it helps.....You can always put it back to where it was. You don't have to put the black plastic cap back on but I usually do...

The machine must have the service door in place and they run best with good airflow to keep them as cool as possible. Some MH installs are not good for that issue. Not enough cool air able to be pulled in that service door opening sometimes......To close to outer door and no louvers in that door. They get hot and it affects fuel system.....

I own 2 of them and occasionally have similar problems.....They get to hot and may shut down.....and being lean does not help....

07-02-2020, 06:10 PM	#5
Rich Biebel VIP Member Join Date: Jun 2007 Location: Northern New Jersey suburbs Posts: 2,275 Likes: 25 Liked 510 Times in 200 Posts	Re: Onan 4000 with shut down but will restart Make sure the oil is not too full. It can be in the middle of the dipstick good area. Most of the new machines are set a touch lean on the carbs mixture. For best CO Emissions.... You could try richening it up 1/2 a turn, out.. The black plastic cap on the carb is a tamper proof item that prevents you from backing that mixture screw out past where it was set at the factory. It allows just a small amount of change for altitude....leaner.... The black plastic cap is knurled and so is the mixture screw. It just presses on. You can very carefully with a bent screwdriver pry that cap off. Carefully because the mixture screw is brass and can be broken. It's a needle inside.... Richen it 1/2 a turn out from it's most rich setting and see if it helps.....You can always put it back to where it was. You don't have to put the black plastic cap back on but I usually do... The machine must have the service door in place and they run best with good airflow to keep them as cool as possible. Some MH installs are not good for that issue. Not enough cool air able to be pulled in that service door opening sometimes......To close to outer door and no louvers in that door. They get hot and it affects fuel system..... I own 2 of them and occasionally have similar problems.....They get to hot and may shut down.....and being lean does not help.... __________________ Rich Biebel S/C 1479 Last edited by Rich Biebel; 07-02-2020 at 06:15 PM.