View Full Version : mechanical fuel pump fitting

Bobby D
04-18-2012, 12:08 PM
Marine fuel pump fuel in 3/8 NPT fitting, fuel out 3/8 inverted flair fitting correct?

04-18-2012, 02:23 PM
I can't tell from the picture (and I do know the difference), so take a trip to the local hydraulic shop.

Bobby D
04-19-2012, 11:52 AM
I do business with a shop that should be able to help me figure out what I need. It won’t be long now; goal is to complete wiring this weekend and set the motor back in the boat next week to take measurement for the built to fit risers.

04-20-2012, 11:28 AM
I think this is the same Holley pump Bobby, and if I recall, it's also NPT to the fitting you use to supply the carb.

Bobby D
04-20-2012, 03:35 PM
Sure looks like the same fuel pump thanks for posting the picture.

04-20-2012, 04:46 PM

Most fuel pumps use a 3/8" male NPT pipe threaded 90* Weatherhead street "L" fitting to screw-in the pump's outlet with the other side of the 90* fitting having a female inverted flare for a matching flare tubing "nut".
Your steel, or copper fuel, line to your carb itself should have the actual male flare nuts flared on this tubing .
I like to double flare these flare nut units just like brake lines.

The other intake side of the fuel pump usually has a 3/8 ", or similar brass hose barb fitting for the marine fuel hose to push-on with two SS screw clamps.

There are also many other ways to do this with various other syle fittings & aircraft lines.

NAPA, or a any similar good auto supply store, can fix you up with the proper "Weatherhead " brand forged brass fuel line fittings.

Bobby D
04-23-2012, 03:26 PM
Thanks for the reply and good explanation it helped me sort things out.

joseph m. hahnl
04-23-2012, 09:27 PM
You can convert the NPT to a flare with an adapter and use metal gas lines. They are simple hardware store items. The gas lines need to be coast gaurd approved for fire retardent for a specific amount of time. That is why it is best to use steel lines as they don't melt, and they go way beyond the requirement


04-27-2012, 03:23 PM
Question on the steel fuel lines and fuel with ethanol. Could rust/corrosion become an issue over time?

joseph m. hahnl
04-27-2012, 06:05 PM
I would think corrosion would be non existant. I think they are some what presurized all the time and oxygen isn't really present like in a half full gas tank. I haven't had any problems ,but stainless steel is always an option .