Chumley

I disabled the EGR valve on my '73 motor when I put on a new carb.( at least I think I did, I dissconnected the vacuum hose from it) I cannot get the carb to behave on a cold start. When the throttle is opened, the choke is supposed to close and the fast idle cam is put on the high step. When I start th engine cold, it does not seem to be on fast idle and I have to baby feed it gas with the pedal until it won't stall. (usually a minute or so) Would not the EGR valve be in the closed position permanently without any vacuum from the carb, and thus unaffective? I have tried adjusting everything on the carb to specs, including the fast idle adjustment, with no success. I just wanted to eliminate the possible role of the EGR valve in this problem. Any ideas? Thanks, Chumley

joe_padavano

The EGR valve should have no effect on cold starts. It sounds like the choke was somehow disturbed. Next time the engine is cold, remove the air cleaner cover and see if the choke closes. If not, that's the problem.

Chumley

The carb is a rebuilt '72 Q-jet from U.S.A. Parts supply. Runs fine except when cold. The cover on the choke is not the original with the index marks, it's just a solid piece of plastic, so I don't know for sure where it's at on the scale. It seems like the fast idle cam is not staying on the high step when engine is started cold. It idles fast for a second or so, then starts to stall until I give it a little gas. It may be possibly worn a bit since it is a used carb. On the matter of idle mixture: I get Rochester dyslexic. Which way do you turn the screws to lean/richen? Also the specs say initial position of screws is 6 turns out. That's where I started from. I've always tuned by getting the highest manifold vacuum with as lean as possible mixture. I guess I'll have to just do some more tweaking till I hit it right. Chumley