my sons grandfather messed his mini dirt bike?

well the only reason it would not run after you take the choke off is nif its running too lean (not enough fuel in the fuel/air mixture .this can be caused by too much oil in the fuel indeed or blocked jets in the carburettor or which sounds more likely water in the fuel !its either got into the tank or the air filter ,HOW DEEP WAS THE PUDDLE?you will need to drain the fuel tank and replace it with fresh fuel then drain the carburettor (the thing the throttle cable goes down to)there should be a small screw on the side of the float bowl which is the bottom of the carb just slacken the screw maybe 1 or 23 turns have a dry contaier i.e a bowl or tub under the carb or under the drain pipe if it has one and look to see if there is water in the fuel when it is in the tub,it will look a bit like jelly at the bottom of the tub ,make sure the fuel tap is turned off or it will keep running out of the carb until the tank is empty.if theres no water in the fuel then its a problem with either the jets in the carb or fuel flow problem reply bto this and maybe i can help you some more ok, adam , bike mechanic as trade

adam bike doctor
January 2006