Help! My '98 454 ATV dies after it gets warmed up (about 6-8 minutes after starting), and won't start again until it cools down. I've cleaned the carb, adjusted the valves, and put in a new spark plug. But no change. It runs perfectly up to the point where it warms up. Anyone know whats going on?

 

Is there any spark? If not it sounds like a coil. If there is, then it must be fuel,check your gas cap vent.

 

When it dies pull the plug and see if you have any spark.

 

After checking the spark and fuel vent line, check your fuel shut off valve. If you haven't used the valve for a while or don't use the reserve, it can build up dirt.