My son got a 110cc Chinese made atv for Christmas and in now experiencing some issues related to running. A couple of weeks ago, there seemed to be an issue related to fuel flowing out of the bottom of the carb bowl and the overflow line. That problem seemed to fix itself and the atv ran great thereafter for a couple of weeks. It has been very cold recently and the atv has become reluctant to run properly. When started, the idle is extremely rough and seems to have a white/grey colored smoke from the exahust.....further inspection revealed that there is slight wet black deposits on the exahust pipe......dont know if that is related to running extremely rich or not? I pulled the plug and it is black and slightly wet. I tried to idle it at the rough idle in hopes of it clearing up....but no luck. I suspect a fuel moisture problem and extremely cold temperatures are to blame......but unsure. I was told to drain the gas, that there may be moisture in the system. Could symptoms like this be related to cold and fuel moisture? What should I do? It ran great prior to this incident.

GB

 

I may be corrected on this but, from what I understand, the Chinese quads, when new, come with a gel pack in the float bowl. [to protect it in shipping] It is designed to dissolve with the first tank of gas. It is possible that is what caused the float to not cut off the gas inlet and flow out of the overflow tube. It may also be what has fouled the exhaust.

If the idle is wrong, it may be a air/fuel mix issue. You can try to adjust the mix screw to see if you can clean up the idle. Do a search for carb adjustments online to give you a theory on how to go about it.