Just discovered this group, and glad I did. My 415C with a C-85 was running rough at idle for a few weeks, then it began to run rough below 1200 rpm. Now it will not idle, and quits with the throttle back, and barely runs at 1200. A shot or two on the primer and it runs great for about 10 sec, then gets rough again. I hear backfires and lots of knocks. Opening carb heat helps a little. I adjusted the idle mixture screw in, then out, to no avail. Runs fine at 1500 and above. One other thing, my plane has no mixture control - don't know if that was removed or wasn't installed in my model (SN 1480, N94157). I think I've spotted where mixture control should attach to the carb, on the back left side up high. That little lever with the ring at the end is positioned full foward. But if it was the mixture, I would think it would run fine at idle and not rev up. Mine does just the opposite. Seems like it's not getting enough fuel at low rpm?
Any ideas? Thanks in advance Bill Buhles Davis, CA
