Only 3psi on new electric fuel pump

[Nextelbuddy]

Mercruiser 5.7 carb.

I had to replace the mechanical fuel pump with my new vortec build as I'm no longer using a camshaft that supports the mechanical fuel pump.

So initially I purchased an Edelbrock electric fuel pump rated at 4-8psi...

People told me oh you can't use that because it's not marine rated.

So I left it in the package and and went ahead and purchased a Carter Marine fuel pump at the recommendation from others. It's also rated for 4-7psi

I have a brand new anti-siphon valve in place 3/8 marine rated fuel hose going to the Mercruiser fuel filter housing with a new Mercruiser fuel filter. And then 3/8 marine fuel hose going from the fuel filter to my Edelbrock carburetor 1409 that has a hard 3/8 fuel line and it had an extra port for a 1/8 npt fuel pressure gauge so I put one of those in.

We did our first engine start today on the new engine build and it started fine but only about 3.5 PSI of fuel pressure Of course I feel pressure doesn't really go up when you blip the throttle.

I don't want to lean out the fuel on this new engine build and I would really love to see at least in a minimum 4 PSI.

Considering throwing in the Edelbrock electric fuel pump and see what fuel pressure is just for comparison.

Any thoughts ok why a brand new Carter marine electric fuel pump only putting out 3psi?

I read a lot of the reviews on Amazon and of course there's a few complaints of the fuel pump not getting the proper fuel pressure.

 

[Bondo]

Ayuh,...... Cross check the gauge,.....maybe it reads low,.....

 

[nola mike]

I am not impressed with Carter at all. I went through 3 pumps last season. First one 9 psi, flooded carb. Second was 2.5 psi. 3rd was 3psi, and is still in there. Runs fine, but the connections are garbage. They're just push on, and I've had 4 occasions where a lead has fallen off and killed the engine (and made my heart sink until I realized what was happening). This year had the Carter oil pressure switch fail after a couple of months and almost stranded me on the water. Anyway, point being that even at 3psi mine apparently delivers sufficient volume.