Put a 2 sping set up on it man....
Return To Idle Problem
Thread Starter
Racer
Joined: Oct 2007
Posts: 437
Likes: 104
From: Birmingham AL
AL Events Coordinator
Return To Idle Problem
I have a repetitive problem with the idle of my ’66 300HP 4 speed car. When I am driving normal around town with the engine fully warmed up the car will not return to a normal idle without me tapping the accelerator (very slight touch of the pedal). Normal idle is around 800 RPM and it will return to around 1,200 RPM. At times the car will return to idle with no problem but the norm is for me to have to tap the pedal. The carburetor is NOS and has been on the car about a year. Should I get a heavier return spring or is there something else that I need to address to correct the problem
Racer
Joined: Oct 2005
Posts: 478
Likes: 5
From: Redlands CA
It sounds like your throttle linkage and or throttle butterfly assembly is binding somewhere and causing the throttle to stay open a bit. A heavier spring would probably work. I prefer a double spring setup incase one spring breaks you still have the engine returning to idle. I had a single spring break once and that was enough for me.
Safety Car
Joined: Nov 2000
Posts: 4,761
Likes: 138
From: Clinton Township MI
Cruise-In III Veteran
365GTB4 is right on about where it's probably binding. If your linkage is original, it's probably due for replacement.
Here's a link to a post I made with pics of that linkage. DID solve the binding I was experiencing:
http://forums.corvetteforum.com/c1-a...r-removal.html
Jim
In God We Trust!
Here's a link to a post I made with pics of that linkage. DID solve the binding I was experiencing:
http://forums.corvetteforum.com/c1-a...r-removal.html
Jim
In God We Trust!
Team Owner
Joined: Jul 2006
Posts: 22,167
Likes: 4,172
From: Kannapolis NC
Look at your fast idle cam after the car is warmed up. If it has cleared the linkage as it should, it's probably your accelerator linkage binding, but if the fast idle screw is still resting on the cam after warmup, your choke/fast idle mechanism is what's binding. I just this afternoon took my choke apart and cleaned the piston in the choke body that pulls the choke and linkage off. It was binding at the top and causing the fast idle to stay engaged even after warmup. Or it may be as simple as loosening your choke a little so it cuts off completely after warmup. The first step is to determine if it's the fast idle or the accelerator binding.
Burning Brakes
Joined: Dec 2010
Posts: 1,223
Likes: 360
From: Southington CT
Don't rule out the mechanical advance weights not returning to the zero position which would hold the timing more advanced than your base setting thus raising your idle speed. But I don't think this is your problem as your rpm differential is kind of high for that to be your issue.
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Burning Brakes
Joined: Dec 2006
Posts: 768
Likes: 1
From: Round Rock Texas
Don't rule out the mechanical advance weights not returning to the zero position which would hold the timing more advanced than your base setting thus raising your idle speed. But I don't think this is your problem as your rpm differential is kind of high for that to be your issue.