mopowers
Well-Known Member
I acquired a slightly used 650 proform mechanical secondary carb (67212) for my 340. I took it apart just to check it out and it looked great. When I put it on to fire it up on the 340, I can't get the idle lower than 1000. The primary and secondary curb idle speed adjusters are all of the way out and nothing is preventing either linkage from fully seating. The fast idle screw on the electric choke is all the way out as well.
I sprayed carb cleaner around the base and can't seem to find a vacuum leak. The vacuum advance is disconnected and plugged as well and I've got a PCV hooked up. The 4-corner idle mixture screws are all about 1 turn out, which gives me 12.5 on my AFR gauge. Before I tried this carb, I had a 670 street avanger that ran fine. The only other change I made with the carb change was I installed a Carter mechanical fuel pump with pressure regulator set on 6 lbs.
What am I missing here? Any ideas why I can't get this darn carb to idle down?
I sprayed carb cleaner around the base and can't seem to find a vacuum leak. The vacuum advance is disconnected and plugged as well and I've got a PCV hooked up. The 4-corner idle mixture screws are all about 1 turn out, which gives me 12.5 on my AFR gauge. Before I tried this carb, I had a 670 street avanger that ran fine. The only other change I made with the carb change was I installed a Carter mechanical fuel pump with pressure regulator set on 6 lbs.
What am I missing here? Any ideas why I can't get this darn carb to idle down?