Fuel delivery problem, I think

Working on the '68 V-6 over the weekend, we were never able to get it running for longer than a minute. After a couple pumps of the gas pedal and choke open, it would fire up and run normal for a few seconds, then fall back to just sputtering, then rev up to fast idle again, then sputter, over and over again. Often would stall during the sputtering part.

We replaced the original gas tank with an MTS plastic one the last time we worked on it and it ran that weekend without a problem.

I'm thinking it's acting like there's a vacuum in the tank. Buddy thinks that we may have ignored the placement of the tubes in the tank during fuel pickup install when we did the tank. We didn't come up with these theories until after we left, so we couldn't test them.

Either of those sound right, or do y'all think it's something else still?

 

Do you have a see-thru fuel filter that you might be seeing bubbles in the fuel. That would tell you if pick-up tube, etc is bad?

 

Too dirty to tell if it's see-through right now, but I'll check that. Thanks.

 

Originally these came with a return line from the fuel pump to the tank. According to the FSM this was to prevent vapor lock. I had issues with mine with the port on the pump plugged. I ran a return line and solved the problem. Others have not had a problem with the line plugged. Also check the vent in the gas cap. I had those issues on my motorcycle. Wax had plugged up the vent hole.

 

I had the same problem with mine when I first bought it. Apparently, the orange rtv that was on the sending unit gasket turned into jello when exposed to fuel which then clogged the fuel line.

 

Sounds like how my jeep acted once when I was trying to get it started.. then, I tried starting it with the choke on(butterfly closed), and it started up and ran good I guess I thought I could start it and keep it running with the choke open by just feathering the throttle.