I have a 1967 Cutlass Supreme. I've recently replaced the motor with a 350. The fuel pump has only two lines. There is no fuel in the carburetor when I park it for the night (in the morning) and no fuel is being pumped when I turn the motor. When I prime the carb with gas, it will start on the second crank and then there is sufficient flow of fuel to the carb. If I accelerate it, it will not provide enough fuel.

I have replaced the fuel pump with a new fuel pump. Any idea what can be causing this?

Cheers,

 

Yes. Leaks in the fuel lines between the fuel pump and the tank.
Either rust pinholes in the steel portions (including the sender) or tiny cracks in the rubber hoses.

- Eric

 

My guess would be the hoses. I spent the day replacing all the rubber hoses connecting the steel lines. Many were hard as a rock and cracked.

 

Ok, but no fuel smell, I'll have a look at those lines, they are almost 50 yrs old after all.

Thanks for your reply gentlemen,

Cheers,

 

Doesn't matter. The holes don't need to be big enough to let fuel out, only to let air in.

- Eric

 

Does your fuel filter have the anti-drain back valve? It's #1 in the picture.

 

Thank you once again for the wonderful replies. It's like, I go to bed and when I wake up it's a new day!!! Complete with new replies and new support for my yesterday's problems.

Does my fuel filter have *the ant-drain back valve? My carb mech thought to leave it out as unnecessary because they sometimes stick.

I'm going to do my testing today: check the fuel pump by placing fuel containers before and after the pump. Visual all my lines.

I will report back.

Cheers,

 

After replacing the rubber hoses at the fuel tank if you still have the same problem it could be due to the carburetor leaking. Q-jets are notorious for leaking fuel under the primary jets. This can be fixed by rebuilding the carburetor and sealing the bottom of the primary jets with epoxy.

 

Considering that the rubber hoses between the tank and the pump are on the suction side of the pump, they aren't going to let fuel out anyway...

Note, pay particular attention to the hoses between the tank and the hard line above the rear axle. I've had this problem before on several cars at that point.

This is primarily a problem on the 1966-67 Qjets with the pressed-in sheet metal plugs. Qjets made after that use thick spun-in aluminum plugs that are pretty much leak-proof. Unfortunately, ever since the Doug Roe book, everyone points to this as a Qjet flaw. I've never seen this on a 68-up Qjet in 40 years of working on these cars.

 

Kind of like this?

Edmonton-20130908-00218_zps1e0e3d5a.jpg

This is what I added,

Edmonton-20130908-00220_zps49b9f420.jpg

I tried to take a video, this is while the car is running. The bubble only fills to 1/8th so yeah, still drawing air. Next I'm gonna drop the tank (yuck).

Cheers,

 

Those clear filters don't have to fill up to be working fine, but, yeah, a hole like that.

Do check your tank hoses as well - they may be worse!

- Eric

 

So Joah, did you solve the mystery? Was it the crack in the line after all?

 

Yeah, it was a small crack in the line directly from the gas tank. Really hard to believe that a small split in the line that doesn't leak gas would cause so much grief.

Cheers,

 

PS thanks for your interest. We'll be retiring the ol gal for winter soon.

 

Try putting a small hole in a straw & see how hard it is to drink from.

 

So YOU'RE the guy who keeps doing that to me!

- Eric

 

Lol, MD!
I was following this thread with interest since I replaced all my fuel hoses (not hard lines) and wanted to make sure I didn't bung anything up. Thanks for the update.

 

I just want to take the time to say thank you to all the people who have helped me with my car so far.

Cheers,

 

You're welcome!

- Eric