ATV will idle, but giving it gas causes it to die - why me


Old 04-09-08, 05:36 PM
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Join Date: Sep 2007
Posts: 23
ATV will idle, but giving it gas causes it to die - why me

It's a Honda Foreman 400 4x4 model TRX400FWV.

I've taken the carb apart and cleaned it, it was in remarkably good condition - no build up. I went ahead and took out the jets, etc, carb cleaned the passages, etc. Put it back together.

Problem existed before and after the carb cleaning. I've adjusted the idle speed mixture screw. Here is one thing. If I adjust the idle speed one way, it idles roughly, but dies as soon as i give it gas, if I adjust it another way, it idles roughly and slowly speeds up and just as it seems the motor wants to speed up on it's own, it dies. If i adjust the rough idle so that the REVS don't increase, and I give it gas, it dies.

Any help would be appreciated.


Last edited by Rain Man av; 04-09-08 at 05:37 PM. Reason: 'cause I'm a moron
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Old 04-09-08, 09:08 PM
Join Date: May 2006
Location: Iowa!!!!!
Posts: 3,773
When it's speeding up on its own you've leaned out the mixture. All that is normal. You've probably got some cleaning yet to do. A good catch all for cleaning is a bath cleaner with a compressed air blow dry. NAPA has one that comes recommended.

If you want to try cleaning it on the machine, take out the fuel in the tank, and replace it with about two quarts of fresh gas. Add carb cleaner in a strong concentration. Start the engine and adjust the idle as smooth as you can get it. Then slowly close your choke and open the throttle slightly to increase your rpms. The choke should keep it running.

Don't over rev it, but if you can keep it running with the choke, let it run at the higher rpms for a short time (about a minute). It will pull the carb cleaner up through the midrange circuits and will help to clean it out. If it seems to be running better, slowly open the choke back up and see where you're at. If it doesn't seem to be any better, think about a bath cleaner.

Hope this helps,

Old 04-10-08, 03:04 PM
mikeTN's Avatar
Join Date: Dec 2007
Location: Nashville
Posts: 635

don't know much about ATV's but if it starts and idles then dies upon acceleration, sounds like a vacuum leak. instead of pulling fuel/air it pulls only air? just a thought!

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