We just fired up my friends new 383. We are using a carter 172 GPH fuel pump. we have it set up like this;
3/8 hard line from tank, we had to use AN fittings to get it to go to the 10AN inlet on the pump. then 8AN coming out of the pump.
The carb keeps running out of gas and i keep having to refill hte fuel bowls. We are not getting any fuel pressure either. If you unscrew the outlet barely any fuel comes out, but if you unscrew the inlet a decent amount comes out. Something else is weird because the rear fuel bowl on the double pumper has gas in it? so something isn't working correctly here. Also i don't think the pump is defective because it did this on the first pump also. It was leaking and my friend went to tighten the inlet fitting and snapped the whole inlet off of the pump. So hea had to replace it wiht a new one, and they both do the same thing! Any guesses?

fuel pump pushrod in correctly ??

Can fuel in rear bowl be from filling it?

if you depress the arm on the pump in the palm of your hand you will feel suction and hear suction from the inlet. Or depress it on a bench top, the sound is obvious.

The rear fuel bowl will have gas because you filled it. When you run the engine it is running mostly off the primary if someone is feathering the throttle.

I had a brand new Holley 6 valve pump that did the same thing you are experiencing. A warranty replacement fixed that. Also, I see above the comment about the pushrod. Make sure it is on there.

ps. Have you correctly identified the inlet and outlet sides of the pump??? - just checking.

it should be the correct fuel pump rod, also i have no idea why the rear fuel bowl has gas?? the front sure doesnt, and i never filled the rear bowl. Also i am 100% positive of the inlet and outlet

Did you try the pump lever push test ?

no, not yet, it is on my friends car, but what is weird is that the other pump which was new did the same thing. Someone suggested that the 3/8 hardline was too small, but that doesn't make sense to me.

You did check to be sure the rod is moving right?
Pull the bolt out of the upper early engine mount hole in the front of the block to be sure it isn't over about 1/2" long. It will lock the rod if it is.
If the rod was free when you put the pump on never mind ;)

yeah, i mentioned that to him. He did have a header bolt in that hole. He said it wasn't holding the rod. But now that you mention that to me, i am going to make him double check that. thanks for the idea

Originally posted by cody:
no, not yet, it is on my friends car, but what is weird is that the other pump which was new did the same thing. Someone suggested that the 3/8 hardline was too small, but that doesn't make sense to me. Cody, i have a 3/8" hardline to my Carter 172gph and it pumps enough for 11.60 @ 117.31 mph.

Now with that in mind, i have a few questions.

did you guys turn the base of the pump for clearance? How far? and did you check to see if it put the diaphram into the wrong spot inside the pump.
Been a while since i took mine apart, but its something worth checking into.

yes, he did turn the base, in the instructions it said it didn't make a differnce. Another good point to check though.

Actually, It won't matter how much or how far you rotate the base, the diaphragm is circular, covers the entire bottom section and is not affected by the rotation of the base.

If he removed the two screws that separate the two lower sections, then let me know.

if it does the same with both pumps then maybe your primary float is stuck up not letting any gas in the carb

Originally posted by baddbob71:
if it does the same with both pumps then maybe your primary float is stuck up not letting any gas in the carb ..I agree.

as i mentioned, its been a while since i took that pump apart.

If it were a float stuck shut, then it would be making pressure.

Verify your float levels and make sure there isnt any junk in the needle and seats.

I just read this post so I don't know if you've found out the problem. I am going to assume that the pump never produced any fuel pressure. Strange, but I had a similar problem with two pumps recently (a Carter and a Holley) where I had to pour fuel down the outlet line to prime it. For some reason, if there wasn't some fuel on that side of the pump, the thing just pumped air. It's worth a try, only will take you a minute. Incidentally, I've been using aftermarket parts for over two decades and never had this problem before.

Mike

i have seen the push rod lobe wear down on cams before-if every thing else checks out look at that-esp. since the old one did it also(also ck your fuel line for a kink)

is it fixed?

no not yet, lots of good ideas. What was the deal about the 2 screws when taking apart the pump. I was thinking of pouring gas down the outlet line also. Whats really weird is that the secondary bowl has gas?? also the float is fine, and has been verified.

Strange situation, in a previous entry you said there was gas leaking from a fitting on the first pump- so evidently there was gas at the pump at that time and priming it wouldn't help. Disconnect the fuel line and attach a piece of rubber line to the end so it routes to a bucket, fill your primary float bowl again and start the car to see if any fuel is being pumped. If fuel flows out you know it's a problem with the float/needle/seat assembly. If fuel doesn't come out then it may be your cam lobe, fuel pump pushrod, pump, fuel line, or filter. Bob