the petcock is leaking when it is on the res position. the spark plug is black and there is some black liquid coming from exhaust. this four wheeler has been sitting out side for about 3 years i cleaned the carb already. i dont know what else to do. it wont even start with engine starting fluid.

 

Has it got spark?

 

I agree...Spark?
I think your motor may be full of fuel. If so, hold the throttle wide open and crank till it starts.
OK,,,,,,,,,,,I read your other post...
Do a compression test.
FYI: starting fluid isn't a great thing to be spraying in a 2 stroke. I use WD-40.