Scootergptx is right about the vent hose, it is the drain that hangs down but it's closed off unless your draining your fuel bowl

 

how fast do you hit the water? I go through a mud pit by my house all the time and its almost above the tires and mine doesn't cut out. i don't even have my airbox on anymore. anytime i cross water i allways go a slow as possible though.

 

i do not go fast at all but i know when you ride wheelies and stuff gas will occasionally run out of the overflow tube on the carb, can water get in it?

 

the carb has an internal passage that connects the drain tube to a tube going to the top of the fuel bowl. when it tips up or over fuel can travel through that internal tube and trough the drain tube. i don't see how water coud get in through that tube but you might try blocking it off. you'd think if water could travel through it all the guys that install snorkal kits and do deep water crossing would have thiers blocked off.

 

filled spark plug boot with dielectric gel and seemed to help alot but still had some sputters in 8 inch deep water any other ideas

 

i also relocated the carb vent hose to the handlebars and checked all intake tubes and they are all tight

 

If your exhaust exit gets under water it will cause your engine to bog down and die.