Drain the carb into a clear glass container and the gas and water will separate the water will look like balls of water.
you have to know the make of the carbeurator. Kehin and Mikuni make most of them i know of.
ATV carberator adjustment 1996 ATV lt4wd
you have to take out the carburetor and then clean it
on the carburetor
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.
try cleaning your carburetor thoroughly
float valve or float are bad
will your 4wheeler tend to stoll after pushen the coutch to far on it?
Carburetor not adjusted correctly
Just order a new one, You can find them on the Internet for around $25.
Having water in the gas tank will work its way up to the carburetor.
how do you know if your yamaha atv is a 400 or a 450