Help, I just finished having a pair of 575sci motors built for my '38 Scarab.The motors are superchilled and dynoed at about 650hp each.Here is my problem,I was originally told (2 and a half months ago) that I could return the fuel (has Aeromotive fuel pumps) back to Mercury racing 35-8m0000493 fuel filter/water separators after the regulator .Now that the motors are done I am being told by the builder that I need to return to the tank for best results. My issue is that the boat has 2 motors and four gas tanks -1 main 150 gal ,2- 25 gal saddle tanks and 1- 50 gal aux. tank under the rear seats.It is unreasonable to return to all these tanks. I would have like 10 ball valves in the engine compartment not to mention all the tank fill are forward of the engine compartment in the gunwales. I was considering going with a fuel cooler in the return line back to the filter assemblies.Maybe the integral one on a sea strainer like the one CP products sells. Any advice please.Mike

Hmmmmm,not one response yet? My question may be a little too "wordee".Anyone?

I've got mine returned to the fuel separator. Same issues as you. Best case to the tank, 2nd best to the separator.When I got my boat it was returned to the front of the pump, that is bad as it aerates the fuel entering the pump.

Just return to the main tank only. All the other tanks should feed that one.

Acually the fuel tanks do not feed into each other. There is a long fuel manifold with six(I think) manual hand valves. So you have to manually switch each tank on. I was thinking of maybe returning to just the main tank and just using an electric fuel pump to transfer from the aux. tanks to keep it full.Then I just have to return to one filler neck.

That is the thing to do. Imco does make a switching valve with dual returns for EFi with dual tanks.....but it will not help you in this application.

My OL has two aux tanks and two eletric tranf pumps to keep it full. Works pretty good you just gotta remenber two turn them off. But at least you can fill the main with out stopping.