1963 FI Fast Idle

[Lawrence S.]

https://youtu.be/MqhWwC3dZBY

The You Tube video is a clip I just took of my 1963 FI that is fast idling after applying fuel (or Vacuum)...goes up to around 2200 RPM and stays there and than slowing backs down to around 850-1000 RPM.

Checked return spring...checked for vacuum leaks (hear fan belt pully in the background I think)..screws to plate tight. Wondering if the spill plunger is sticking but wanted to ask others out here for options and any thoughts before taking the unit off. Appreciate any advice...thanks!

Larry

[Dan H.]

Re: 1963 FI Fast Idle

Acts like a sticking throttle shaft, remove return spring and check for any binding.
Dan

[Jim L.]

Re: 1963 FI Fast Idle

Acts like a sticking throttle shaft, remove return spring and check for any binding.
Dan

I agree with Dan. It's not un-common for the brass throttle shaft bushings and the throttle shaft to wear such that the throttle sticks. You might do a Bubba-bandaid by doubling up on the return springs but the better solution is to replace the bushings and polish the throttle shaft.

In any event, it's not the spill valve.

Jim

[Rick A.]

Re: 1963 FI Fast Idle

Agree with Dan and Jim

[John D.]

Re: 1963 FI Fast Idle

Larry, Is this issue something new? Was the FI unit recently rebuilt? Around 10 years or so ago there was a repro spill valve that had a sticking "nail" in it. But I doubt you have one of those.
Besides what was said here check to make sure the choke shaft is not binding. That could be causing the fast idle. Remove the air cleaner hose and look in the bore to see what is going on with the choke butterfly. Most all midyears I work on have issues with thechoke shaft sticking. Then I have to ream the hole that the shaft goes thru.
Did you have the air meter apart recently? Is the big brass throttle butterfly centered in the bore?
Years ago I restored a '64 FI that acted like yours. The goof I made was just what I just said in last sentence. Large butterfly not centered i the boreand that acted like cruise control.
Some of the repro inexpensive blue spring loose their tension after a while. Franz Estericher taught me this long ago.
Cad plating on the throttle shaft could be your problem. If so do what Dan, etc said. Remove the shaft and polish it. When you reinstall the shaft make sure to have some clearance on each end so the shaft and the shaft leaver don't hang up on the air meter body.
Grease and carbon will cause your issue.
The 63 shop manual FI section has a lot of info on the air meter. Lots of pics. John D