starving for fuel

[americanhorses]

I'm sputtering if I try to accelerate too fast and intermittingly.

Here is what I have:
73' 302
BC Q-jet
Very clean tank with all new lines, pickup, filters, fuel pump and selector switch.

I'm thinking it is the accelerator pump/seal.

I put a electric fuel pump I had right at the tank with a toggle on/off. When it sputtered I hit the switch and ZOOM. I have no idea what kind of pressure is produces so I don't want to leave it on.

Where should I start? how do I determine if the accelerator pump is bad?Should I get the right electric pump and bypass the old mechanical or get a (insert brand here) mechanical pump?

 

[demesauce]

What do you mean by accelerator pump? You don't need 2 fuel pimps inline. I'd suggest removing the mechanical fuel pump and running a quality electric pump. Then install a fuel pressure gauge so you can make sure there is no fluctuation when you acceleration.

I've got a fuel pressure gauge you can use to help diagnose the problem

 

[SHX669]

If you have a high pressure pump { above 5-7psi} you can install a combo regulator/gage unit.
SHX

 

[John Marinan]

If changing the pump doesn't work, have you adjusted the part time throttle?

 

[americanhorses]

What do you mean by accelerator pump? You don't need 2 fuel pimps inline. I'd suggest removing the mechanical fuel pump and running a quality electric pump. Then install a fuel pressure gauge so you can make sure there is no fluctuation when you acceleration.

I've got a fuel pressure gauge you can use to help diagnose the problem

I'm meaning the pump in the carb itself. I know I don't need 2 between the tank and carb. I hate the mechanical with the Q-jet. After just a few days, it's hard to start.

I may take you up on the gauge. I may have one...I'm such a packrat

 

[americanhorses]

so the question I guess is. How to check the pump in the carb?...or rule it out.

 

[broncnaz]

If you look down the throat of the carb and work the throttle you should see fuel squirt as soon as you hit the throttle. If no squirt then your accelerator pump is bad. Usaully a sputter or hesitation is the sign of a bad accelerator pump.
As for running your electric turn it on and look down the throat of the carb again if you dont see fuel leaking then the electric pump shoud be fine. Or if fuel is shooting everywhere then you need a regulator.

 

[gnpenning]

I hate the mechanical with the Q-jet. After just a few days, it's hard to start.


This may not be the fuel pumps fault. This may be a seperate issue. Qjets when made have a couple casting plugs put in after casting that are known to leak down the road. Very common. Some rebulid kits come with a plug to help seal this. Many just epoxy the plugs. Some replace the plug.

 

[carmi]

I had a similar problem that turned out to be excessively gapped spark plugs. Would sputter every time I hit the gas. Also hard starting. If you can see the accelerator pump nozzles shooting fuel then your accelerator pump should be good. You can also check to make sure your getting 5 to 7 psi fuel pressure using a regular automotive vacuum gauge.

 

[americanhorses]

Great...Thank you!