I am running an Eldebrock 600cfm (electric choke) carb and recently removed a 1" spacer from my SBC as I did not think the carb spacer was adding anything but it did feel like it was robbing a little low end torque. Right after removing it I started having a bobble in the throttle response just as I gave it gas (just off idle). I have checked for vaccum leaks and everything is good. I do not remember making any carb adjustments when I added the spacer. Last night after running the car when I turned it off I got the dreaded deisel effect and it did not want to turn off (never had this happen ever). It was about 90 degrees out, I was running the AC (which I rarely do) and I was sitting in normal traffic but I do not believe it was loaded up when I did get home. After I gave it some revs it turned off fine. What could cause this. to lean or to rich. I know the factory sets the Idle Mixture setting (IMS) at 2 turns out. when I check mine this morning it was at just about 1.5 turns out. (which should mean it is on the richer side of the factory settings.). I do have a chrome intake and it was hot out ( but the car was running around 190).. would I be getting heat soak since the carb is now closer to the intake and there is lots of heat from the chrome. any thoughts
I've run the Edelbrock carbs on several motors and they always run better with a four hole spacer under them. much better signal and mix especialy at low and mid rpms Paul
Put the spacer back under the carb. Mine used to do the same thing. Especially when I got off the freeway from an extended run. I put a 1" spacer under the carb and it solved my problem. You were getting heat soak from the engine heat...especially with a chrome intake and a hot day. Most carbs use a setting of 1 1/2 turns out to get it to run and then you fine tune it from there. Put a vacuum gauge on it and set the carb to the highest vacuum you can get by adjusting both idle screwsin or out. If you don't have a vacuum gauge set it to the highest idle...then back each screw out about 1/2 a turn.
I did forget to mention one item. I had adjusted the idle up about 200 rpm before the deiseling occurred. Just took it for another ride and again it would not turn off until I put it in gear and the RPM dropped. I have it idling at 800 in park and around 550/600 in gear. well, I guess it time to put he spacer (4 hole style is what I was using) back on, if no one has another other suggestions...
Just put the spacer back on and what a world of difference in response. No hesitation or desieling issues. All better For those of you with single carbs and an automatic, what does your car idle at in gear.
When I had the single carb on the sedan I had it idling about 750 r.p.m. in park. It would idle about 600 to 650 r.p.m. in gear. Thats with about a 485 lift cam. I had a 600 edelbrock and a 750 at different times. They both idled about the same. Glad to see you got the problem solved.
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