This is my first 4-wheeler, so i'm not sure what the problem is. It runs fine but if you punch it (floor it) at idle it just dies unless you let off. I took the air box out and sprayed some carb cleaner into the carb while it was running. That didn't help. But I did notice that when it does do this that the gas appears to actually be spitting back out of the carb. I think that would explain why my air filter smells of gas?? My other problem is I don't have the owners manual, so I don't know if there is any adjustments. I see on the left side of the carb towards the bottom there appears to be an adjustment. Its a screw with a spring between it and the carb. What does this adjust?? Should I get the factory service manual or is a clymer's just as good??
Thanks Guys
Chris

 

Well, this is not uncommon. I have seen others post about it. There are 2 adjustments you can make on the carb; idle mixture and idle speed. The one you can turn by hand is idle speed and I can't remember the set-up for the idle mixture screw but you need a screwdriver to turn it.

Mine does the same thing by the way and I haven't been able to tune it out. Try setting your idle speed a little higher. Maybe you could make it better with the idle mixture screw, not sure if it will help though.

 

See my reply in the Yamaha forum.