Combines Air in fuel systemIJ

Going back a long time now! late 70's. constant problems with power and starting on an l2. Found the breather hole on the fuel tank was blocking up with dust,creating low pressure in the tank,fuel starvation and loss of power and fuel being sucked back into the tank from the fuel system after stopping engine. Cured by placing a small can over the fuel cap to stop the dust from getting in the breather hole. Perhaps this may help.

I would make shure all the air is out of the system by bleeding the pump by loosening the screw on it and pumping with your new hand pump until pure fuel is comming out. good luck

I destroyed 2 diesel pumps on an l2 before figuring out that little breather hole was partially plugged.