engine is running sluggish , i have a clear fuel filter before the carb the gas is not even filling the filter 1/4 full.

a few weeks ago i changed the fuel pump and still the same problem today,
at increased RPM the engine is starved for gas ( I THINK )

i remember the filter being almost fuel when running and the engine ran good.

Is it possible the lobe the pump runs off of is worn and the pump is not moving and pumping enough ? Any advise would be great.

the truck is a 74 the engine is a transplant an has pertronix ignition.

Thanks

 

If your sure the carb isn't even 1/4 full. You may need to adjust the float in the carb

Unk Bob

 

Not the carb. The fuel filter is not filling , maybe the pick up in the tank is clogging up, thoughts ?? Thanks

 

Could be a clogged fuel filter, even a bad fuel line that is sucking air instead of pulling fuel to the carb.

 

See how it runs off a 2.5 or 5 gal gas can setting on the ground (under the fuel pump) or on the fender to trouble shoot the fuel pump. Some times the fuel filter will not fill up all the way, just the inner filter part will be wet or when the pump pushed fuel it will surge in the filter.

And then put a little LOW pressure air back down the fuel line towards the tank. LOW PRESSURE to clean off the pick up tube sock filter. Also insp any and all rubber flex fuel lines for dry rot. Should only have 3, tank sending unit to solid line on frame, solid line to fuel pump in eng compartment and silid line to rubber on each side of your filter to the carb.

Have you replaced the accelerator pump on the carb? Any other inline fuel filter you missed? Maybe down along the frame rail?

 

Thanks. All great advice. I will look at it closer. I did change the filter between the pump and carb I installed it a couple years ago. The carb was a rebuilt 3 years ago. The truck is a 74 f350 car carrier I don't drive it everyday, I thought the new pump fixed it. But today a hauled a old truck and was fuel starved up hill and taking off. I am sure it's not timing.

I remember the fuel pump would be nice and full of gas wile running. Something with the fuel has changed. The tank is in can behind the seat. Thanks

 

Thanks. All great advice. I will look at it closer. I did change the filter between the pump and carb I installed it a couple years ago. The carb was a rebuilt 3 years ago. The truck is a 74 f350 car carrier I don't drive it everyday, I thought the new pump fixed it. But today a hauled a old truck and was fuel starved up hill and taking off. I am sure it's not timing.

I remember the fuel pump would be nice and full of gas wile running. Some with the fuel has changed. The tank is in cab behind the seat. Thanks

 

At least an in cab tank sending unit is way easier to access. But I believe they can be a hard to get replacement item?

Maybe try adding an electric fuel pump with a manually adjustable fuel regulator?