I was wondering what would cause a serious hesitation in my 1970 f-100 with a 390, when I floor the gas pedal all my truck does is die or try to die, I have played with the ignition advance and the fuel mixture, but nothing has helped, any suggestions?

Ashes to Ashes
Dust to Dust
Without ch*vs
our tools would rust

 

How’s the pump shot look? With the motor off, look down the carb. while you open the throttle. The shot should start immediately when you do and continue without any sputtering along the way.

Also check for vacuum leaks with a can of carb. cleaner. Spray around the base of the carb, the intake manifold where it meets the heads and all vacuum lines and fittings.

Another thing to do is disconnect and plug the vacuum advance and then see how she acts up.

A good starting point for you initial timing is around 10 degrees BTDC.

Barry

 

I had a Holley once that had something blocking the pump nozzle. It's amazing how badly it runs without the pump working. Also might check to see if the fuel pump is keeping the carb supplied with gas.

 

I checked the auxillery pump shot and it was two steady streams, but I still have to check the vacuum
thanx all if you could add anything else it would be great
Steve

Ashes to AShes
Dust to Dust
Without ch*vs
our tools would rust

 

I have been thinking of the cheapest way to add a electric fuel pressure gauge. That would let you know for sure if the fuel pump was keeping the carb supplied with fuel. The complete units are priced too high. I found a sensor on the net for about $29 that changes resistence with pressure. It would be easy to add a meter to it to read pressure.