I bought my son a tao tao 125cc and it ran decently for the first few trips out but after sitting about two weeks it won't start. It tries to kick over but won't actually fire up. It was recommend to loosen the overflow screw on the carb to ensure the carb is getting gas and it is. I pulled the spark plug and grounded it and it does in fact spark. The spark plug was black and slightly wet with gas. Not sure if this is normal, I'm new to all this. After wiping the spark plug off it fired up for just a brief moment but died again shortly after and would not start again. After just a few minutes of trying the fully charged battery dies. I'm at a loss. I would greatly appreciate any help or suggestions. Thanks!

 

The starter does drain batteries as it pulls quite a bit of cranking amps. That sounds like a carb issue to me, as I usually work on small engines but not quad atv engines.

That sounds like the float in the carb is stuck and flooding the engine.

Might try a replacement.