Resurrecting this thread. Probably unrelated but here goes -- round six or seven with these $#!%%&ing carbs.

The car was idling weird -- kinda lugging, from 1500 down to 900 (1500 is the normal cold idle in Park.) I shut if off, took off the scoop and air cleaners, checked vacuum lines, checked the chokes (the butterfly on the foward carb had stuck closed a couple of weeks ago), everything looked good. The rear butterfly valve seemed a little too open, so I adjusted the choke to even it out with the front.

Fired it up again, idled it for a few seconds -- seemed to idle great, now -- dropped it into reverse, and BOOM!! Engine dies, backfire and flames. Big flames coming out of the rear carb.

Here's what I don't understand -- why would it idle fine, and then blow up when it's dropped into gear? I'm going to rip that carb apart in the morning. I know I at least need a new power valve. . . .