Hi everyone, I have a warmed over 355 that I am running in a 69 Camaro SS with a Muncie 4-Speed. It has a nice sized Comp Magnum 280H cam, flat top pistons, roller rockers, edlebrock RPM airgap intake, Accel HEI ignition, Holley 650, etc. I am having trouble with the idle. It keeps moving around on its own. I will set it when I start the car, and drive it around for a while. It will run fine, and then when I come up to a stop light and push the clutch in, it will either try to shut off, will run fine, or it will be idling a couple of hundred RPM's higher. It dosen't do any one thing consistently. All vacuum lines are new, as well as the intake gaskets and carb gasket. Does anyone have any ideas? I am running 15 degrees of timing per my engine builder. I have also noticed that after I have run it for a while, and the car is at operating temperature, that if I shut it off, and then try to restert it, it takes a while to fire. I have to pump the pedal several times for it to start. When it finally fires it almost sounds like itis loaded up until it clears itself out. Could all this be caused by the float sticking? Any help would be appreciated. Thanks

 

Sounds like the choke is sticking, or the choke linkage is binding. you can also try putting loc-tite on the threads of the screw if it doesn't feel tight.

As for the timing, if you have a vacuum advance, the try 10 BTC and play with it from there.... you should pick up some power and make it easier to start.

 

It could be a sticking float, wrong float level, or it could be the rpm at idle is to high, i.e. the throttle plates are to far open at idle. This causes a loss of vacuum on the idle circuit and is common with older "high lift/duration cams".
You'll need wire gages to check the thottle plate opening gap. The most common fix is to drill a couple of small holes in the thottle plates. Get the "How To" Holley book for specifics.

 

I agree with the last guy. It's either that or the carb idle circuits are full of crud from old gas.

 

Put some more timing in it for one thing.

Check the float level...sounds like they may be too high.