Aerovee Turbo Fuel Flow

[pfhoeycfi]

My turbo aerovee engine had been running pretty good with the #2 needle but I decided to try the # 2.5. This change was prompted by what I saw as low fuesl flow data and some intolerance to pulling the mixture.

Anyway, with the number 2 needle I experienced a small RPM drop, less than 50, during static runup at 2000 - 2500 RPM. During flight test my CHTs remained consitant between primary only and secondary only operation at 3000 ish RPM indicating the timing was correct.

After installing the 2.5 needle the engine seems to operate pretty good with both the primary and secondary on together or when just the secondary is on by itself. When I switch to primary only during runup I now get a drop of about 100 RPM. Similary, in flight at high rpm, say 3000, when I switch to primary only I get a noticeable drop in RPM with some roughness that I seem to be able can lean out to some extend, which to me is odd since I dont need to lean with the secondary only or both.

My initial guess is I'm still to rich but I'm not confident in my guess. Any thoughts on what I'm seeing? I'm going to fly again tomorrow and recheck the timing and play with the mixture some more.

peter