Set it to (on) for riding and storage, it is vacuum operated and wont pull fuel unless engine is running. In (pri) or prime, it flows fuel like a regular on/off petcock, so if your needle and seat is worn, you will fill the motor up with liquid gas. (res) is reserve, for when you run it out of gas and need to get back to the trailer to fill up, allows you to use the tiny bit of gas left in the bottom of the tank.

 

Thanks for the info, I had been riding with it on (pri) and it would eventually stall out. Is it possible that that setting is just to (prime) it and not for riding?

 

Prime is used to refill the carb after you had it off or drained it for storage, you can run it on prime, but if the needle and seat leak by, it may overfill the carb. Dont know if that would cause your stalling problem or not.

 

Ok, thanks...!