Rebuilt 302 stumbling

[neoxman]

After running my rebuilt 302, recently i found an intake leak (fixed by re-torquing the intake manifold bolts) and another problem. The truck would stutter or stumble on moderate throttle.

I thought it was ignition at first and re-timed and even swapped in a new coil i had laying around. After no luck with the ignition i looked into the carburetor as my mechanic mentioned it might be the accelerator pump on my carb (edelbrock performer).

I removed the carb checked the accelerator pump and found a hair in it. Cleaned it tried it ... no luck ... still stutters.

I'm fed up.

Some background info:
I've had my 302 built and running for about 6 months. It's not fully broken in but I'm also finishing things on the interior which keeps me from driving it. I start it every couple weeks or so.

[fordman]

the accelorator pump in a carb is for that extra blast of gas on the demand to go . it is usually bad when you are at a stop light and you puch the pedal down and the car just sits there for a second and then goes. it can also produce the problem you describe too. i am unsure about the way you describe this though. i am not good on fine tuning stuff. it sounds like a fuel related problem to me. junk in the tank plugged fuel filter messed or dirt in the carb. something in the fuel system.

did the leaky intake and carb probelm happen at the same time or close together. or did you tighten the bolt and then run into the stumbling problem?

[neoxman]

the intake and stumbling happened at the same time. My mechanic warned me of slippage of the intake gaskets but i seriously doubt that happened as i can rev the engine if i jam the throttle. it's only on moderate revving. if i'm very careful also i can rev the engine smoothly if i go very slow.

[RTG_RACING]

Vacuum leak maybe?

[neoxman]

it may be ... however i've used carb cleaner to check for that. and i think the severity of the stuttering is so bad that i can't imagine it being a vacuum leak. what happens is it will cut out when revving and fire and cut... if i try to rev more it will stall out completely.

[neoxman]

i was thinking it would be the vacuum advance but engines still don't cut out when there's no advance (i'm not sure). Plus if a condenser was bad idk if it would start. thinking of all the ignition parts.

[RTG_RACING]

Check the plug gap. Does it load up? Any black smoke?

[fordman]

this is still saying accelorator pump to me.. i also wanted to ad that if you have a auto trans there is a vacuum line on the modulator that can also come off or go bad and leak. it could be that you just have a piece of dirt some where in that carb that only gets sucked up at a certain point.

[neoxman]

yeah plug gap is fine. no smoke. interesting you should mention the trans. I plugged the port on the back of the carb. the only vacuum lines coming off the carb are in the front. one for pcv valve and another for the dizzy. I've tested the alternate dizzy port and i'm on the correct one. The auto trans modulator is connected to one of the branches of the vacuum tree that is mounted to the intake behind the carb. Should this be connected to the carb instead?

[fordman]

no the trans vacuum is suppose to hook to that tree.

[neoxman]

just went and looked down the ports that are fed by the accel. pump. I can see a nice flow when i actuate the throttle... so it seems like the pump is working fine. I'm thinking i got some dirt in the carb somewhere or i have a really clogged up fuel line/filter.

[RTG_RACING]

Maybe the pump going bad.

[BobbyFord]

the intake and stumbling happened at the same time. My mechanic warned me of slippage of the intake gaskets...

Not trying to bag on your mechanic, but properly installed intake gaskets don't "slip".

[neoxman]

well he's my uncle and they could have been installed improperly. i wouldn't take anything he says for granted as he's owned a shop for over 40 years. Could be that i mis-understood something he said.

[BobbyFord]

Have you tried running it with the vacuum advance disconnected?