C3 - 69 L68 idle question

[John A.]

Hello,

I recently replaced the center carb on my 69 L68. It was a service replacement and I found a correctly dated replacement. I had it freshly rebuilt by the carburetor man. After installation, I went through and timed the car and set the idle and mixture setting. The car starts and runs fine. But, after it reaches full operating temp (after driving it) the idle settles to about 1000rpm. Any ideas on what would cause the idle to creep up like this?

Thanks in advance..

[Joe L.]

Re: C3 - 69 L68 idle question

John-----

There are probably quite a few possibilities. One that I would suggest might be an incorrectly adjusted butterfly valve which remains slightly open at idle.

[Roger Legge]

Re: C3 - 69 L68 idle question

Another possibility for a fast idle could be mechanical advance weights hanging a little bit. A slightly different symptom for this would be a higher idle, after driving, then the idle slowly returns to normal idle speed.

Roger

[John H.]

Re: C3 - 69 L68 idle question

Could also be something as simple as a slight bind or minor misadjustment of the throttle linkage (rod from carb to firewall lever); have seen more than one like that, that "wouldn't idle down".

[John A.]

Re: C3 - 69 L68 idle question

Roger,

Thanks for responding... I will put the timing light back on and see if there is a timing advance issue. I'm thinking it is more of a fuel problem, leaking by somthing after it warms up. Still hunting...