ok so i got this 300ex in on a trade it starts right up but idles really really high i got a carb off my buddys old one cuz the idle screw was broken and it still idles the same speed tryed turning it down and nothing... any ideas?
Check the throttle cable pull the black cover off the side of the carb and see if the linkage is traveling all the way back to idle. if the quad is stock set the pilot screw 2 1/2 turns out from seat. check to make sure the choke lever isn't loose too. but I will bet you have the cable too tight. If so Loosen the jam nut on top of the carb and turn the 90 in until about 3 threads are showing and lock the nut down, hook up the cable and try that. Also check your cable for cuts kinks or the plastic sheathing separating from the inner winding