Universal M25 fuel filter

I've got a Universal M25 diesel with the electric fuel pump in my '86 E35. Anybody know how many gph that fuel pump is putting through the system? I'm thinking of going to a smaller sized Racor filter to give me another inch of room and am thinking 20gph on that fuel system would be plenty. Have a 30gph filter in place now and think that is overkill.

Thanks

Kevin Wright
E35 Therapy
Port Townsend, WA

Hi Kevin, I just went through replacing my Racor filter with a new NAPA Gold 3426 cartridge. The unit is mounted on the starboard side of the engine compartment, out of the way. Not sure how many GHP the electric fuel pump puts out but our M25 gets well over two hours per gallon.

As I understand it, 30 gph makes sense because, although our diesels use little fuel, a robust fuel system recirculates (and filters) more, both lubricating the engine and polishing the fuel in the tank.

Regarding Racor spin -on filters, each of the models R20P, T and S is rated for 30 gph. The difference is microns: P=30, T=10, S=2.

Rick's is a 6-micron filter.

It is mentioned here in this thread, along with the option of a Racor 500-series assembly, with its less expensive paper filters.

We all have to decide what level of filtration, meaning micron rating, is right.

For the primary filter, the consensus here lately seems to be 10 microns (I am using 30). Two-micron filtration for the primary is in disrepute (clogs fast).

As to the secondary filter (the little one on the engine), I read this: It is there only in the event the primary filter fails completely. The secondary filter then clogs immediately and shuts down the engine to protect it. I like the logic of that.