Firstly, the forum search function seems to be broken again. I searched for SU HS6 and several permutations and got *no* results.

Anyway. I finally gave up on the HIF6s and reinstalled by older, rebuilt (partially) HS6 carbs on my B20E. I've got an old-style low pressure fuel pump (AC Glass Dome) These carbs now have newer throttle shafts and the cast body has no measurable ovaling...

So, you'd think these would run smooth and tight? Not so. While the B20E started and ran strong, as soon as I tried to lower the idle and/or lean the carbs, the engine refused to slow down. The absolute bottom end of the idle is 1000 RPMs. The forward carb will adjust a little lower by itself, but the rearward will not idle any slower. I've leaned the carbs out quite a bit (max) but that only kills the engine.

This is similar to the problem I was having with the HIF6s. #2 refuses to idle low. I've no idea why, but I've sprayed thoroughly around the carb bodies and manifold and observed no change idle speed or quality.

Any ideas as to what it going on here?