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Is there a need to put check valve's on the fuel return line of each Cummins engine and Gen Set. to prevent back flow of fuel if all the return lines go into (1) tank and if (1) engine or Gen. Set was not running could you get back flow to the Engine or Gen. Set.

R,
DQ

Don't put anything in the return lines.

Ditto what Bruce says. The check valves in the Racors will take care of any flowback, but they are probably not even necessary if the fuel system is tight. The Cummins injector pumps are real tight and don't seem to want to flow back. Some other engines need the return line extended down into the tank vs. just dumping into the top. You are going with the same engines I've had for over a decade, and trust me, just dump in the top of the tank by the fuel filler/fuel gague plate up on the front top of the tank.

Send me an email with your UPS/DHL address and I'll send you the Lee Sr. tube, I'm looking at it lurking in the corner of the shop, it needs a good home. VLR@RKKDLAW.COM

BTW Faithful, Lee Sr. parts are now like gold according to the Lee guy at the FLL show. Lee has no more. Save your old parts.

UV

Compren'de, Thanks Bruce


UV,
I will e-mail you my DHL # tomorrow, Thanks UV

DQ

My engines, of course, are Cummins converted pickup truck engines (don't smoke or sling oil like Detroit dump truck engines, though) - different injectro pumps than the marine version. I had a problem for a long time with fuel draining back to the tank if I let them sit much longer than overnight. I have ball valves on both sides of the Racors, always had to remember to turn them off. I finally took a suggestion and extended the return lines down further into the tank, and the siphoning back stopped. Was also told this works better when running it rough water. I also tried check valves in the fuel lines in front of the Racors, but they don't always work flawlessly.

All it takes is a hairline crack in the Racor bowl to have that overnight flowback take place. I suffered with that problem and changed lines and lift pumps etc etc. It wasn't till my son was standing by the exposed engine when I was trying to start it up that he saw bubbles in the Racor bowl as I cranked. The crack was hardly visible and was on the back side. Changed the bowl and it went away. Walter

Racor fuel filters have a ball check to prevent backflow as UV already stated.

But like everything else on a boat they need to be maintained which involves pulling the Racor apart and put a repair kit in.

I recommend this be done every 3 years. Kits are cheap and its an easy job.

Any other check valve system in the feed line puts severe strain on the primary fuel pump and can lead to failure and can cause excess pulsation in the fuel inlet to the injector pump causing performance problems.

Of course, about the same time I lengthened my return lines, I also changed from the Racor 500's to a set of new 900's. Don't know if my old ones had a crack or a bad check valve, Ernest has them now,.