Kitzy

Iv'e got a new sending unit, new mechanical fuel pump, And I've blown out all the fuel lines. And I still can't get gas to the carburetor. It's a 383 with a carter pump and 750 double pumper carb. Does any one have any ideas on what my problem might be?

Archer

kit -

Most likely there a blockage in one of the lines and don't exclude the filter in your tests.
Disconnect the fuel line before the carb, put the line in a container and crank the engine to confirm.

Less likely would be forgetting to put the fuel pump push rod back, having the wrong size/worn push rod or a worn cam lobe.

Archer

Kitzy

When I blew out the lines I had them disconnected from the tank to the pump, And disconnected from pump to carb. The lines are clean. Like you say the push rod may need replaced. Do they wear out often?

Archer

Kit -

It's pretty rare. I've seen ONE become so worn it wouldn't activate the pump lever.
If you replaced the cam, make sure it wasn't designed to be used with an electric fuel pump (no fp eccentric).

Just for giggles, by pass the filter and report back.
Don't ask why I'm suspecting that ...

Archer

Kitzy

I'll try that, I just bought this charger, And have a lot of reciepts but not much info on the build. Holley 750 double pumper ,Mild flat tappet cam. headers, and complete rebuild. Is what I have receipts for. I'll report back. Thanks.

Kitzy

Took the filter out and reconnected the line, Still no gas. I'm going to pull the push rod and measure it. Also can I put my finger against the push rod and have a friend turn the engine over to see if the rod moves up and down against the cam with out smashing my finger?

RacerHog

I'm not sure using your finger is a good idea...

Archer

Kitzy -

Yeah, your finger is probably not the best thing to use...
Even if it were safe (and it's not), you'd have no idea how much lobe is necessary to move the pump lever.

A safer option would be to disconnect the hoses from both the inlet and outlet ports and turn the engine over. You should feel a suction from the inlet and air coming out of the outlet. Unfortunately, that will only isolate the problem to the pump, but not give you the cause.

If the car came with a mechanical pump, do you still have that pump? You might be able to test it the same way. With the pump off the car, one finger on the inlet and one on the outlet, and manually pump the lever.

If the old pump behaves as it supposed to, try it back on the car and test as you did with the installed pump.

Still betting there's a blockage somewhere in the system - and that includes the carb itself.

Archer

Iowan

Safety first, use your friends finger on the pushrod and yours on the key👍

TVLynn

run a hose from the fuel pump to a gas can See if it works. What happens if you prime the carb

Kitzy

When I prime the carb. the engine accelerates then dies when the poured gas runs out. I think I will run a supply hose to the pump from a gas can and see what I get from the outlet.

Archer

K -

Think about the last place you'd expect a block to be, that'll be it.
Basically you're going to have to go from the pump in both directions and see where you stop getting a suck or blow.

Seriously, I went through the same **** last year. Took a week, but it turned out to be problem with the filter inlet passage.

Archer

Kitzy

I put a hose from inlet of pump to a can of gas and still get no gas. So it's from the pump to carburetor. I ordered a new push rod, As mine looks very worn on one end even slightly mushroomed. It measures 2 -15/16" long.

Archer

k -

Sounds worn, report back when you try the new one.
Hopefully the cam eccentric is still in good shape.

Archer

Iowan

I believe that it can be seen if the distributor is pulled.

ZEN357

I've had bad mechanical fuel pumps right out of the box.

Kitzy

The push rod was the problem, I have plenty of gas now. It's blowing black smoke and loading up. From what iv'e seen so far I'll bet the carb. isn't adjusted any where near where it should be. It is a 383 mild cam and Holley 750 double pumper. Can anyone give me a good starting point on the adjustment? Thanks guys + gals!!

RacerHog

Make sure the choke plate is all the way open......
Make sure the float level is just below the side bowl sight plug holes.
If the carb has 4 corner Idle air mixture screws, Make sure thay are all turned out an even amount... All the same... If it only has two, Same applys...
If it looks rich.... Check for blown power valves....

Just my 2 cents..

Archer

K -

Glad you found the problem!

Bob's description of carb tuning is fine, but if you like pictures/videos, there are a number of them on youtube.

Archer