FYI
Just a guess with a difficult intermittent problem, but I would begin with your Fuel system....Fuel filter, Carb, idle screws, A/filter, etc....

Cleaned up the carb and adjusted it runs better but it still missed and hesitated and stalled , did notice the fuel pump when the motor gets hotter it sucks less fuel, I've always had a back up electric fuel pump by the back wheel, so I bypassed the original mechanical fuel pump and just ran the electric pump, the filter stays half full even when full throttle, but I don't know if the electric pump will last long being on the whole time your driving??

Sam,
It sounds similar to a problem I've had. I too have an electric booster pump that I use to prime the engine after it sits for a week or so. Its mounted in line with the main fuel line near the tank. I have had a problem when accelerating hard getting onto a highway. It runs fine up to about 40 mph and then seems to just run out of gas and starts to miss and hesitate. I have found that if I hit the electric for a few seconds it gets the gas and runs fine again. I have concluded that the mechanical pump can't pull hard enough to pull a lot of gas through the electric pump. I am thinking about ways to get around the problem but for the time being at least I know how to deal with it. After the hard acceleration and brief hit with the electric pump the engine cruises fine at 60-65 mph. It would be worthwhile trying it. Just goose the electric pump briefly when it happens and see if it helps.

Good luck,
Ed

That definitely sounds familiar, I did the same thing b4 to , would flip the switch when it would hesitate or get close to stalling, and it would help, sounds like the same problem, I've taken a few drives now with just the electric pump bypassing the mechanical pump and it's running perfect now, no more stalling and hesitation or miss fire, would be nice to keep using the mechanical pump , but when it gets hot it runs like shit

Are you guys running a standard electric fuel pump, or a "pass through" electric pump designed to allow full fuel flow through it while the mechanical pump is operating?

Rob

Rob,
I'm using an Airtex E8011. I believe this is supposed to allow flow through. I also replaced the Airtex filter (Airtex G-17) that is attached to the pump but that didn't help.
Ed

Ed,

Some pumps will allow some fuel through, but when really needed will be restricted.
Yours may well be a full flow through style.
Have you removed the line near the carb and pumped fuel into a can to check flow and for dirt/junk?
Did you check the filter by the tank (if present).
Sure sounds like an intermittent restriction, or a volume restriction.

Rob

Mine is a flow threw as well, the mechanical pump does fine when it's cool, once it gets warm is when the pressure goes down, maybe it's a gasket , the mechanical pump had new components in it when I got the car, I've just switched to the electric pump , all the problems I was having are gone

Just a thought. In the 48-54 parts book a 'screen,- tank outlet' is listed, is it possible that it is partially plugged and not allowing enough gas to flow to the engine?. The parts book also states that it is soldered in place. I don't recall seeing that in my Pacemaker tank when I had it out 20 years ago. GM cars (and others) have used a screen/filter at the end of the pickup tube and i have replaced a few of those over the years on customer cars that were reeking havak on the driveability of the car..

:angry: 🙁 , took it for a ride and right back to how it was, and it's pretty cold out side in wisconsin today, get to the stop sign and push in the clutch and stalls, gotta flutter the gas to keep it running

Sam,

Have you checked for vacuum leaks?
Vacuum line, loose manifold, loose carb, really worn shaft or bushings on butterfly valve.
You said you cleaned carb, is the float set correctly?
You might try some hard stops. If it dies at a stop sign, but not when gently stopping in your garage, that will offer more clues.
If it regularly dies from hard stops at different speeds, something is moving that shouldn't, possibly a wire shorting or a choke, or a heat valve changing the air/fuel mix.
If it doesn't die from hard stops at different speeds, but just dies now and then at stop signs, I'm going to stay with intermittent fuel restriction.

Rob

You may have a fuel problem, but you need to check the compression. It really sounds like the valves are tight and/or sticking. the valves being tight can cause the engine to stall,stop running when letting off the accel pedal ,lack in power,etc,... .

Never thought to check the intake bolts all of em where loose, runs like brand new again , happy as hell

Sam, how would all the intake bolts come loose?. Did you have this off as well?.