Recently, our high temperatures have been in excess of 100 deg. and our 1975 3KW Onan (gasoline) vapor-locks after about 45 minutes of running.
The rubber fuel line enters the generator compartment at one bottom corner. Then a steel line goes over the top/back (over the exhaust pipe) of the gen. Then a rubber hose back to the floor to the fuel pump.
I re-routed the tubing and removed the steel line. Now the rubber tube comes from the fuel tank, through the floor at the opposite corner then directly to the fuel pump; thus bypassing the over-the-generator configuration.
It now runs fine even in 105 deg ambient temperatures.
NOW I have created another issue: the gasoline drains back into the tank when the generator is not in use! It takes several seconds of cranking to get the gas to the carb after sitting over night.
The generator set is well above the fuel tank and there are NO air leaks in the system.
So my basic question is: If I put a (barbed) anti-siphon valve in the line near the fuel tank am I going to experience fuel problems later because of the valve?
Sorry it is such a long-winded question, but I do need some advice.