I have a B7100 Hst that for one is leaking fuel at the top of the injector pump.Just a seap. I know that is a replacement of 3 o-rings. It smokes like its not getting the right amount of fuel, slight haze, not loosing oil or coolant. But the kicker is that I have no fuel returning to the tank from any of the injectors. I have even swapped a set of good injectors and same deal. Could my pump be goin out?