JUst put the pcv on quad ran great. Then the check engine light came one died and now it won't start stranded at the dunes for 3 more day and no quad!!!
It looked pretty clean and dry. May go buy one tomorrowi would still try and replace the plug if youve got a spare. if its a weak spark, it may not be enough. ive run into this problem with lawnmowers- even if the plug is firing when youve got it pulled, it may not be enough oomph when its flooded with fuel and stuff. does it look pretty dirty?
although... i dont think a dirty plug would trip the check engine light. sounds like an issue with fuel.