Hi all! I am new to ATV connection and was hoping to get some advice with a problem I am having with my wife's Yamaha. It was sitting for about 2 years. Yes it had gas in it. I originally tried to start it and it ran like junk. back fired, popped, wouldn't stay running, etc... I pulled the carb and took it apart. the inside was green and nasty. I bought a rebuild kit and thoroughly cleaned what I was not replacing with carb cleaner. While waiting for the parts I drained the tank. (gas was very cloudy) I then filled it half way two or three times and shook it to try and clean it out. The last time the gas looked good when I drained it so I figured it was good. I rebuilt the carb and reassembled everything and the thing ran better than when it was new. Started right up and purred like a kitten. I kept checking it for a few days and same results. Now it sat for about 3 weeks and I went out to start all my quads and it will not stay running again. Starts with the choke on but when I shut choke off it dies. Did I do something wrong or miss something? I can get it moving and it seems to run ok but as soon as I let off the gas it dies and I have to use choke to start it again. What could have happened in three weeks???? Any help is appreciated!

 

Did you treat the gas with an ethanol additive? Might should have. I have been through what you are experiencing and found the only way to keep my carbs clean is to use Stabil Marine Formula in the gas. Can't keep anything running well anymore without it, too much ethanol in gas now days.

Sounds like your pilot jet is clogged again.

 

I did not. I am going to break it down again and rebuild it again. Afterwards I will add the additive as well as a fuel filter. Thanks for the advice

 

Broke carb down 3 times and still the same problem. Any other ideas? ANYBODY?????

 

I can only think of two things to check.

First, look at your fuel petcock, the one that turns the gas off at the tank. Drain the tank and take the petcock off and take it apart. There may be some trash inside the valve that's not letting the gas flow freely, or on the screens on top of the valve.

Second, adjust the valves. Probably not it, but everytime I have a quad that gets hard to start, it's telling me the valves need adjusting.

 

The best thing to do each and every time you ride your ATV is at the end of the day, turn the fuel to off while it is running and let the bike run until the carb bowl is out of fuel and it stalls. That will make sure that the float doesn't stick in the closed position. 9 times out of 10, you can't start because the fuel can't get down to the float and run through the various circuits. No fuel in the carb, and it no run. BUT, it won't be clogging up the circuits either. Also, when you jump on your machine for teh first ride of the day, always, always, always rock it back and forth to re-mix the alcohol in the fuel.
Stabilizers help, but do the above and it will solve your problem.

By the way, that green gunk is the alcohol crap. I get that whenever I use the old style Stabil. I can't say how well the marine version works since I have sworn off Stabil. But there are other products out there specifically for use in Ethanol mixes.

Good luck on your carb rebuild.