mgistock

I have an Edelbrock 1406 on my 62 327. After I start the engine and the choke opens, it idles about 650RPM. After driving it for 20 minutes or so, the idle increases to 1000 to 1100 RPM. The fast idle cam on the carb is not engaged. The carb was rebuilt when I got it. Any ideas? I checked and there are no vacuum leaks. I run a dual point non-vacuum distributor.

Bluestripe67

Step one. Have you checked the throttle return spring? Does it have enough strength to pull the throttle back to idle position? Dennis

irwiny

I have the same issue on my 66 327 w/Holley 650 and tried the following but haven't figured why this happens with one return spring:

1) added small spacer between air cleaner and carb - no help
2) added stronger spring for secondary vacuum - no help
3) sprayed lube and cleaned the fast idle cam - no help
4) loosened the air filter nut when it was stuck high - worked sometimes
5) bought a new spring that didn't help so I used two return springs - worked the best,

Also tried to add more play to linkage didn't help.

Irwin

leif.anderson93

My '67 L79 had the same issue...this is what worked for me, as well. Bought a new OEM spring that just doesn't have enough "pull". I remove the second spring when judged.

MikeM

Could be the centrifugal weights are hanging in the distributor?

Off the top of my head, the only other way for the engine to gain speed is because it's getting more air either because of whats been mentioned or you have a vacuum leak.