I'm helping a friend with a lt 80 and the fuel petcock doesnt seem right to me. It has 3 positions, on, pri (Prime?), and res (reserve). The fuel flows freely from the pri and res positions but not from the on postition, he keeps telling me this is normal because the fuel system is a vaccum system. This doesnt seem right to me. Anybody have any thoughts on this?

 

that is right they are vacum

 

Then why is the "res" position free flowing? Shouldn't it be like the "on" position. If the "res" is free flowing the why have a "pri" prime?