Miss, bogg, stutter whatever you like

[BigBrett]

hello I’m new both here and to restoration.

I have a 1978 c10, 350 non egr, auto with 4 barrel quadrajet. Here’s the thing. Idles fine, runs fine until you put your foot in it. Then it kind of skips or studders. You can lift gradually and find the sweet spot for what will run normal.

Now for what has been done. 2 different hei distributors, 3 sets of plugs and wires, timing job, valves adjusted, carb rebuilt, all vacuum hoses replaced. Marvel mystery oil, sea foam, 91 gas and octane booster. Ground strap removed cleaned as well as connecting points. Then 2 00 gauge ground wires added to both sides of motor. Probably other things that I can’t remember.

And still she won’t take full throttle.

Any ideas would be appreciated

 

[bedwards]

Don't mean to insult, but did you adjust your accelerator pump when you rebuilt carb? Mine stutters on the lower factory setting but likes the higher one.

 

[Charlie]

 

[mgarland]

Where is the timing set at idle, how far does it advance at a what rpm if it missing it is probably fuel related.
Mark

 

[BigBrett]

Both settings on accelerator pump do same.

I had timing done at a shop so should be right.

 

[Big Chip]

Both settings on accelerator pump do same.

I had timing done at a shop so should be right.

It's worth checking out anyway. It doesn't have a catalytic converter does it?

 

[Craig 85]

I had a similar problem on one of my trucks. It was the seal on the accelerator pump. The crappy ethanol fuel we have here softened the material and would not pump properly.

 

[BigBrett]

It's worth checking out anyway. It doesn't have a catalytic converter does it?

No. I was wondering the charcoal canister has 4 ports with 2 open...do I need to plug them

 

[Rusty Nail]

Both settings on accelerator pump do same

This is the problem.

 

[BigBrett]

This is the problem.

Can it be fixed without pulling the carb off

 

[Rusty Nail]

Sure can - but you'll still have to take it apart!
Probably easier / better to do on a workbench or similar.

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You say "carb rebuilt" above, please provide more detail because this shouldn't be happening post fresh rebuild..

 

[dajn37]

100 percent a carb problem. They sure are fun arent they?

 

[Snoots]

Having to do it again is good for the soul.

 

[BigBrett]

Change linkage to accelerator pump to the closest one and it helped.

 

[BigBrett]

Now for something completely different. What seats will bolt on to this 78?