Engine: It runs....BUT...it runs rough and won't idle

[BShaw]

The saga of my 60 Hawk rebuild continues. Quick recap: rebuilt 63 full flow; edelbrock 1403 carb; Mallory Unilite distr (T-bow); Solo electric fuel pump w/regulator and gauge reading 6 psi.

It now starts up readily but will not idle. Need to have it at least 1000+ rpm to keep it running. Takes throttle smoothy and runs pretty nice at higher rpms.

I think I have the timing pretty close but it doesn't change much when rotating the distributor so I really don't know where I'm at there (keeping in mind that I am in the car with my foot on the gas keeping it running while my bro-in-law plays with the distributor).

I've tried playing with the idle mixture screws but as it cannot run at idle they really won't change anything until I can get the thing to run at 600 rpm (per edelbrock manual). Right now I've set the idle mixture screws at 1-1/2 turns out.

BTW, I have the vacuum advance on the distr plugged as is the carb port. I have also plugged the pcv port on the carb, removed the PCV valve.

So, what would you recommend for ACTIONS and IN WHAT ORDER that might help me get this sorted out logically and effectively?

[jclary]

Absolute pure guess here on my part. If you have the timing and ignition parts working close as you suggest...I am wondering if your float is adjusted too low to allow sufficient fuel reserve in the carburetor. My thinking is that the fuel is not being sucked into the venturi through the idle circuit at low idle air flow. Again...absolute guess that could have some of the experts on the forum embarrassing me with a correction (again!).

[pdrnec]

What coil are you using? I had a similar problem, had a coil with internal resistor - forgot about the pink resistor wire.

[bezhawk]

Check for an air leak.....sounds like a vacuum problem. Drop a chunk of dry ice down the oil filler tube, and tape off the breathers.......check for leaks around the carb, manifold, and other areas. A poor mans version of the smoke tests they charge $$$ for. Wont harm a thing, and there is no dangerous open propane.

[BShaw]

What coil are you using? I had a similar problem, had a coil with internal resistor - forgot about the pink resistor wire.

Coil is a Pertronix Flamethrower. Pink resistance wire is in use.

[BShaw]

Absolute pure guess here on my part. If you have the timing and ignition parts working close as you suggest...I am wondering if your float is adjusted too low to allow sufficient fuel reserve in the carburetor. My thinking is that the fuel is not being sucked into the venturi through the idle circuit at low idle air flow. Again...absolute guess that could have some of the experts on the forum embarrassing me with a correction (again!).

Possibly, I guess. However, the carb came from my original motor where it worked like a charm.

[BShaw]

Check for an air leak.....sounds like a vacuum problem. Drop a chunk of dry ice down the oil filler tube, and tape off the breathers.......check for leaks around the carb, manifold, and other areas. A poor mans version of the smoke tests they charge $$$ for. Wont harm a thing, and there is no dangerous open propane.

COOL! (pun intended). However, I think the only place I can buy dry ice is some 70-80 miles away where I got some about 15 years ago to pop some hail dimples out of the roof of my pickup truck.

[Milaca]

Might the carburetor need internal cleaning being that it hasn't been used for a few years? May be plugged up with old gasoline having turned into varnish. Just a guess.

[PackardV8]

Doesn't Pertronix recommend a full 12 volts with no resistor?

[BShaw]

Might the carburetor need internal cleaning being that it hasn't been used for a few years? May be plugged up with old gasoline having turned into varnish. Just a guess.

I did put Sea Foam in the gas tank and removed the idle mixture screws and sprayed Sea Foam in there (and in the carb top) then blew it out after letting set for a while. No change. Any other cleaning I need to do on it?

BTW, any good tune-up guys up our way? I really don't have a lot of time to myself these days as my dad needs daily care now. It would be great for me if there was someone good who does house calls!

[BShaw]

Doesn't Pertronix recommend a full 12 volts with no resistor?

I don't know but the coil was on my other motor/distributor with a Pertronix conversion and I had no ignition problems. I'll check that out though.

[showbizkid]

My first thought, before reading any of the other replies, was "vacuum leak". I agree with Brad - I'll bet you're sucking air somewhere. That would explain the evening-out at higher revs.

[JoeHall]

Isn't that the same car & carb, a couple of weeks ago, you said was spewing gas out of the top ?

[BShaw]

Isn't that the same car & carb, a couple of weeks ago, you said was spewing gas out of the top ?

Yes. When I cleaned the carb after that happened, specifically when I removed the idle mixture screws and blew air through them, one appeared clogged at first but opened up after another shot of Sea Foam. Anyhoo, that appeared to solve the gas spewing.

[JoeHall]

Speaking of vacuum leaks, there was a thread a couple months ago here, about a vacuum hole being left open in the electric choke housing on some late model Edlebrocks/AFB clones. I inspected a new one, removed last year from a car I bought, and found that hole open too. The car also ran as you describe yours when I first got it, till I swapped the carb out. I'd suggest doing a search for that thread, since it also had a good pic of the hole. Then, inspect your carb and, if that hole is open, try plugging it up, and see what happens. (This is, assuming you are running an electric choke on yours.)