<VV> irregular idle

[Mikeamauro at aol.com]

"...My 63 Monza 900 3-speed is plagued with an inconsistent idle after  
warmup, varying between a very fast idle (~1500 RPM) and a near-stall at  about 
600 rpm..."
 
It sounds like the throttle plates may not consistently be  finding their 
"home," idle positions (as determined by  the idle speed adjustment screw 
adjustments). This situation would  occur following coming off the fast idle 
cams. I experienced a problem  which sounds a lot like yours: turned out to be 
the screw, on one of the carbs,  which holds the linkage lever to the 
throttle shaft, had worked loose. The  return spring, and all associated 
linkages, were properly driving everything  towards closing the throttle plates to 
the idle position. However, the last  link--the connection between the 
throttle shaft and its actuating  lever--was sloppy. This allowed one of the 
throttle plates to remain in the  off-idle position... most of the time. Before 
finding the loose screw, in an  effort to get the idle down, I had under 
adjusted the idle speed screw on the  offending carb; hence, occasionally, when 
the throttle plate DID happen to  drive all the way "home" (like when 
tapping the gas pedal at idle), the idle  speed was to low for a comfortable idle. 
Check... If you can wiggle  the lever on the throttle shaft, side-to-side, 
the connection is  loose.      
 
Mike Mauro