Sbc 350 idles high what else can I do?

I have a sbc 350 with a edelbrock 1406 and hei dist. I have it set 10°btdc the idles at 650 rpm and I set the air fuel screws at the highest vac at 15hg but all seems to idle high and run rich, what am I doing wrong here what else can I do?

 

carb needs rebuild or you got a vac leak some place ..but id bet on the carb is shot ..

 

While the 1406 can have a vac leak, either the base gasket or the secondary shaft, usually you will run lean. The air mix adjustment may make little difference if you do have a vac leak. I assume you disconnected the vac advance to set timing. Hi idle will give erratic timing especially with a light curve kit in the hei. 650 sounds ok though. I don't know what cam you have. Some of my bigger cammed engines idle at 1000. Carb may just need a good cleaning and/or needles and seats. Good luck. peace

 

That's a big question. You should be able to back off the idle speed screw to the point the motor dies. If not, you have air coming in somewhere. Vacuum leak around base of the carb, bad hose, perforated vac pot on the distributor advance or a stuck pcv valve. Cap off all the lines in turn until you cause a change. Fix that one. Make sure that the butterflies are closing fully when the screw is backed all the way out. One of my pals just set a Holley down on the bench too hard and unknowingly bent the secondary stop so that the secondary butterflies wouldn't close all the way. Took days to find it.
The rich condition will be impossible to address until you fix the air leak. Start with float level and trash in the needle and seat. From there, make sure the idle screws aren buggered up. It should idle Ok at 1.5-2 turns out on both screws. Then you have a jetting issue. That could be jets or mabe the power enrichment needles are not dropping down far enough. Check the springs, clips and make sure the needles are not bent or anything.

That should get you started.

 

a friend of mine had one of these that ran rich BRAND NEW! fuel pressure regulator fixed the prob.don't ask me why i have used dozens of USED ones and never had a prob(knocks on wood)

 

are you using a pro comp hei from china. mine would not idle below 900 changed out the cheap hei back to my points now it runs fine

 

Had a situation similar to this a LONG time ago. High idle (although 650 seems fine to me) and only one mixture screw made a difference. I ran a oxy/acet tip cleaner down the idle mixture screw hole. One side was blocked. You should be able to run a tip cleaner in and see it down the throat of your primaries.

 

I had a buddy who picket up a gasket with the bores that were smaller and the gasket would hang up on the butterflies. His idle wouldnt go down either.

 

Have you tried disconnecting your throttle linkage? Maybe the linkage is too short and holding it open?

Just a thought.

 

I have had an afb, a 750 edelbrock and a 600 edelbrock on various motors, all ran rich w/o a regulator. electric or mechanical pump, didn't matter. mr gasket regulator always helped. might not be the cure, but it helps.

 

Check the fast idle screw on the choke.

 

Almost 5 years ago, I'll bet he got it by now

 

^^^^^^^^ good info though,need to "review" every once in awhile.

 

My wife tells me that I am not real smart.