I bought my son a chinese 4 wheeler with the hensim 70cc motor about 2 year ago. He loves it but he normally just rides it a few hours and a low speeds. Well we took it to grandmas house and he rode it full trottle for hours in the heat and all of a sudden i hear it bogg down and i couldnt get it to start after that. I later changed the spark plug and changed the oil, but it will only run for a few seconds and shut off especially if you hit the gas and sometimes it wont crank at all but if you wiggle the spark plug wire it will start up but for only a few seconds. Im pretty good at working on small engines like lawn mowers and weedeater. I'm going to pull the carb and spray it out, but ive been looking to see if there are some recurring problems with these motors like if the coil goes bad or if maybe he overheated it and the ring is bad . I keep it mantained so its a real surprise that it wont stay running, any trouble shooting advise would really be appreciated, because if i dont get it running ill never hear the end of it until i buy another one. I know it was cheap but it ran good.

 

i have a 110 dont know if its the same carb set up but there was a little plastic spacer in between the carb and intake it craked in half the thing wouldnt idle when you stoped and would cut out al ot i removed it and runs fine know