troubleshoot 1bl carb racing intermittently

[hplacecf]

hi.

newbie here.

I have a 1977 Chevrolet c10.
l6 250.
1bl carb.


looking for suggestions on how to troubleshoot the following issue that I have had since I purchased the truck couple of months back.

sometimes when I start it - engine can be warm, cold, or steaming hot - the engine races like it is in a very, very, very high idle. much higher than just a 'normal' high idle.

the way I 'fix' it is to shut it off, then restart it, and all is well.

when this happens I have looked under the hood at the carb while it is happening. I checked all of the linkages, etc. I can increase the gas as if I was pushing on the pedal all the way, or tapping it as if I wanted to get it off of a normal high idle - but, none of this does any good. only shutting it off 'resets' it.

I have sprayed the inside and outside of the carb with carb cleaner and checked that all of the linkages are not catching up anywhere.

i have never seen this before.

any ideas?

thanks!


note: I got it off of ebay, from a dealer, so no way to speak to the original owner.

[D13]

I found on mine the choke kick off lever had a slight burr that would cause it to bind and not kick off with the throttle. Mine would start fine clold but popping the throttle would not let it idle down. Starting hot woul go to a very high idle. I have to manually get it off the first step of the high cam. haven't had time to fix it yet, probably have to rebend and poilsh the linkage.

[hplacecf]

Originally Posted by D13

I found on mine the choke kick off lever had a slight burr that would cause it to bind and not kick off with the throttle. Mine would start fine clold but popping the throttle would not let it idle down. Starting hot woul go to a very high idle. I have to manually get it off the first step of the high cam. haven't had time to fix it yet, probably have to rebend and poilsh the linkage.

thanks for sharing.

I looked, but that is not my case; everything looks fine with the linkage levers.

[hplacecf]

anyone else have any experience or ideas for this strange problem?

thanks