Anyone know what would cause the hot idle to not drop to it's initial setting when the throttle is released (300 RPMs too high)? Blipping it always brings it back down, as does switching off the ignition and restarting. No amount of fiddling with any of the linkage lowers the idle, and the teapot was recently cleaned/rebuilt. Performance fine otherwise. Not a real problem, just curious.

6 VOLTS/POS. GRD. NW INDIANA

I have seen were the rivet on the carburetor throttle linkage was loose on the butterfly shaft. It only was loose enough to allow the shaft to turn if you either grabbed it or as you say "blipping" Just peen it again if the problem.



Worn throttle shafts will also do the same thing to the idle.



Another thing to check is your timing. If somehow a vacuum signal is getting to the distributor and advancing it your engine idle will increase. Hook a timing light up at the same time and take a reading.



marv

Check that the little eccentric fast idle cam at bottom inner part of auto choke is free and lubricated so it can fall back when choke warms up, it then drops off the adjustment screw and idle normally returns back to normal.  

  AussieBill            YYYY    Forever Y Block     YYYY

 Down Under, Australia

Marv,



"Fiddling" included trying to twist back the butterfly shaft. No help.

Re: the timing: Kind of a "chicken-or-egg" question. Increasing the idle speed advances the timing. Advancing the timing increases the idle speed. Regardless, doesn't explain why just turning the key off, & back on to re-start would lower the idle.

6 VOLTS/POS. GRD. NW INDIANA

Check that the little eccentric fast idle cam at bottom inner part of auto choke is free and lubricated so it can fall back when choke warms up, it then drops off the adjustment screw and idle normally returns back to normal.[/quote]



Bill,



Pony tech made same suggestion. N/A, as "fiddling" included inuring the F.I. cam was free.

6 VOLTS/POS. GRD. NW INDIANA