71 corvette low idle
Thread Starter
Burning Brakes
Joined: Oct 2004
Posts: 801
Likes: 17
From: Middletown Delaware
71 corvette low idle
71 vette rochester carb automatic. 500 rpm when in gear. I did a search and have tried several things without a change. The distributer is rebuilt with the correct vacuum can, I have tried ported and manifold vacuum. I have checked for vacuum leaks and isulated the engine from the rest of the car. the exhaust is new. If I adjust the idle in gear to 600rpm when I take it out of gear the idle speed goes to 1400rpm. The vette runs fine otherwise with no start issues. There is a slight bog sometimes if I stab the throttle from idle but I believe this is because my idle is so low, If I stab it from say 800rpm it runs fine. I guess my question is what next. Thanks dave
Melting Slicks
Joined: Dec 2009
Posts: 3,233
Likes: 657
From: Thunder Bay
Make sure your vacuum advance is connected to manifold vacuum (not ported). Then check your mechanical advance weights. It sounds like you are getting advance at too low an rpm. If your advance starts to come in at 8 or 900 rpm you'll get that jump in rpm.
Thread Starter
Burning Brakes
Joined: Oct 2004
Posts: 801
Likes: 17
From: Middletown Delaware
Vacuum advance is hooked up to manifold vacuum. I tried heavy springs on the menhanical advance with no change but they felt sloppy so tommorrow I will wire the weights in place so they cant move and see if that makes a difference. Thanks
Race Director
Joined: Apr 2011
Posts: 11,183
Likes: 3,335
From: North of Toronto - Ontario
Double (triple) check
Initial timing, not sure of your setup but probably 14-16 deg.
Adjust mixture screws for highest vacuum then lower on the solenoid
Ask Lars for the quad papers and recheck the basic carb settings
Initial timing would be my first guess.
HIH
Mooser
Initial timing, not sure of your setup but probably 14-16 deg.
Adjust mixture screws for highest vacuum then lower on the solenoid
Ask Lars for the quad papers and recheck the basic carb settings
Initial timing would be my first guess.
HIH
Mooser
Thread Starter
Burning Brakes
Joined: Oct 2004
Posts: 801
Likes: 17
From: Middletown Delaware
Update
I disabled the mechanical advance and problem went away. The only way this will work right is to go back to the factory spring and reset timing from there. Dave
I disabled the mechanical advance and problem went away. The only way this will work right is to go back to the factory spring and reset timing from there. Dave
