My ltf 300 suzuki 4x4 king quad is flooding when fuel valve on , placed on res it starts and runs,placed on pri it runs and starts. it floods the air box. fuel valve is vaccum operated, possible dirty float needle or dirt in the diaphram what do you think. my buddy says its a dirty air cleaner. I dout it.

 

Pri should only be used when you've run it out of gas and want to prime the system again. Gas just keeps running when you have it on prime but your float in your carb should still stop the flow. I think your carb needle and seat need cleaning or replacing. The needle and seat should stop the gas flow when the floats get to where they are set at. Yours aren't stopping it and it overflows into the airbox.

Take the petcocks out and clean them too. 'on' draws gas from a pipe sticking a ways up in the tank so's you don't use all of the gas in there but you 'run out' while theres still some sloshing around in the bottom.. Res takes the rest of the gas from the very bottom of the tank, there's no separate reserve tank.
Taking out the petcock shows you this.

 

thanks! I thought that was the problem. Can I just add gum out to the gas or do I have to take the carb apart and clean it. I thought it was possibility old gas since it sat six months.

 

Clean it. Why dick around? You can take the seat off, slide the phillips screw rings out of the way on the rubber plenums and work the carb out the top.