Its a mechanical pump, stock looking, has 3 fuel ports on it. 2 normal line sized, and 1 smaller. Its a good sized fuel pump. What is it for? What is the smaller fuel port for?
This thing pumps so much gas its overpowering the holley carb and dumping a LOT of gas in the intake. So much that its filling the cylinders.
I think the gaskets in the carb finally said, enough is enough too. The engine is a fresh rebuild, just fired last week. fuel pump was new and so was the carb. The last time we built this engine, we didn't use that fuel pump.

Originally posted by fourfiddyfour:
Its a mechanical pump, stock looking, has 3 fuel ports on it. 2 normal line sized, and 1 smaller. Its a good sized fuel pump. What is it for? What is the smaller fuel port for?
This thing pumps so much gas its overpowering the holley carb and dumping a LOT of gas in the intake. So much that its filling the cylinders.
I think the gaskets in the carb finally said, enough is enough too. The engine is a fresh rebuild, just fired last week. fuel pump was new and so was the carb. The last time we built this engine, we didn't use that fuel pump. =
Sounds like might be the mid 70's pump that had a small pressure bleed off that returned to the tank to relieve pressure tht would build up when you shut the engine off & was used with Q jets as they are pretty sensitive to fuel pressure

thanks Mike. What do you think just plugging this off would cause? Would it cause a LOT of fuel pressure?

Sounds like yerbasic stock pump.

Also sounds like you have a defective carb.

Pretty much all fuel pumps from about 69 or 70 on up will have the return line.

Use the return line if you have that connection to your tank; it helps with alot of things. Not least, keeping your fuel cool so that it doesn't vapor-lock, and for best power (cooler fuel is denser just like any other gas or liquid).

Originally posted by fourfiddyfour:
thanks Mike. What do you think just plugging this off would cause? Would it cause a LOT of fuel pressure? Plugging it will not effect the operation of the pump. It will act like a pump that doesn't have a return.

No, it will not cause more pressure in operation as my understanding is it was there to relieve pressure when you shut the engine off as the pressure build up from heat caused the Q jets to leak sometimes.

And I agree with RS that you have a carb problem if it is flooding the engine, not a pump problem.

Have you checked actual pump pressure? That'd save a lot of guesswork.

Had a similar thing happen to my old '67 pickup. Put in a 305 block from a fuel injected car and had to use an electric pump. The electric pump overpowered the needle/seat and poured gas into the intake.

Atleast that's what I thought it was. Used one of those nifty doctor look in your ear things, and it was a little piece of metal holding the needle open.

Rebuild the carb yet?

no, haven't rebuilt the carb. it is a brand new holley. Can I use an oil pressure guage to check the fuel pressure? I have one of those but don't have a pressure guage specifically for fuel. It would be a better test than, "it sure felt like a lot of pressure and fuel" lol
I have a much smaller fuel pump that was used on the engine last year that I have now put on the engine. The engine knocks now, so haven't run it enough to see if it helped. I am hoping that the starter is the source of the knock. If so, I'll try taking out the needle and seat and blowing them out with air.

thanks