I have continued to work on the needle only to come to the conclusion
that I don't think I am going to be able to get the carb tuned without
relocating it. Here are the details:

As of two weeks ago, I almost had the needle shaped properly for the
engine. At that point I felt that it was still too lean at WOT. I
continued to remove material until I almost had it running properly at
WOT and then noticed another trend. At throttle settings just below
WOT, I was no longer able to get the engine to gain RPM by pulling the
carb heat. I also noticed that my CHT' and EGT's from right to left
were becoming increasingly divergent. In short, while the mixture
distribution is "acceptable" at partial throttle settings, it does not
distribute fuel acceptably near WOT.

As I had previously mentioned, the Aerocarb is mounted on its side
with a 90 degree twisted vane right after the carb. Sitting in the
airplane, the fuel "hole" is on the left side of the engine. What I am
seeing is that the right side of the engine is now running rich enough
to start to stumble while the left side is now in tune. This issue was
not uncovered until I allowed the carb slide to fully open (previously
it would remain 5/6" closed at WOT in the cockpit).

At this point, I think its safe to fly if I limit the carb opening to
a setting that is before this becomes and issue. Its making plenty of
power even at that. A bandaid solution at best. I suppose I could
continue to mess with the vane but the I feel that the root issue is
that the carb is not mounted with the needle aligned with the split in
the intake manifold. My Sonerai would not run properly with the carb
misaligned by only 15 degrees. When I straightened the carb so the
needle would align with the split I gained 150rpm and the left to
right distribution was much improved.

I spoke with WW about the issue and he concurred.

I am not sure what I want to do to address this yet. I may try one of
WW's intake manifolds with a different carb. Still pondering the
options.

More to come as I continue to work through this. I think my needle is
now correct but I need to figure the rest of the puzzle out.

Jeff Lange

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