In Reply to: Re: Re: N7 bogging down posted by marshall on June 13, 2009 at 23:27:07:

I would believe the hand pump can leak a bit while pumping and still be sealed up when locked down. I'm sure you can pickup the plunger assembly at any pump shop. The hand pump will not pump up tight for fuel will go threw charge relief valve. I will usually pump fairly slowly and listen for squill coming from charge relief valve. This is same trick I use for determining if there is junk in them valves on many machines (V8 Deutz and some models of Cummins included).

Junk should realy not ever end up getting by first filter and into check valve but I believe some guys fill that first filter and end up with a little chaff in clean side of it. Chaff will flow down the pipe to charge pump and sometimes wedge under check valve so it can not block back flow of fuel as the charge pump piston cycles threw its strokes.