I have a 1991 LT-F4WD 250 QuadRunner that has been acting strange on rides over a half a hour. It seems to lose power for no reason and completely bog down to the point where it stalls if not careful. It weird because it occurs after the machine has been worked for a period of time. Full throttle yields little movement.

The two popular opinions are either there is something wrong with the fuel pump or the CDI box has issues. I am hoping a fellow ATV enthusiast has had a similar issue or knows what this issue might be.

Any help would be appreciated

 

So what did it end up being? My guess is petcock diaphragm has a tear in it.

 

i serviced one of these and the voltage regulator was making it run terribly. i found it by mistake when i unplugged it it ran like a champ. when i replaced it all was well

 

My petcock had a tear, which led to gas being dumped in the crankcase thru the carb. I think it had an extra 2 qts of "oil" in it lol. Figured after I fixed that it would run better. Nope. Then I found a bad regulator. Replaced it and it still ran like crap. Finally I just scapped the cv carb and installed a 230s carb. Runs good now