Crappy seals. Take the ATV to a local workshop and tell them that you suspect the seals on the carburettor to be shoddy.
OR it could be a float problem : sticking float will let fule run out the over flow pipe.
If it's coming out the overflow pipe, then it's likely to be a sticking float.
The Two most common causes for ATV crashes are due to having to many people on the ATV at one time the other main reason for crashes is driving an ATV far to fast.
An ATV can be used for many things including outdoor sports and recreation. If you own a Yamaha ATV and need its vin number look at the plate on the bottom of the ATV.
The leak could come from: hoses, punctured radiator, split gasket...you can put tracer dye in the coolant and search for the leak with a black light after you clean the engine.
carb or timing
An ATV's engine can get flooded if you hold the throttle open for too long. At the bottom of the carburetor, there is a screw that can be opened to drain it.
broken bulb
the 3 bolts at the bottom
on bottom of carb
on the very front bottom bar where the bottom of the brush guard bolts it will be between two stars
Just buy a new ATV, and your problem is fixed!
replace the gasket... that's the best thing gasket about $10 to 20