As Jeff pointed out, this kind of tracking variation is common on the small Continentals. Jeff helped me take out about 1/8" of tracking difference on my A65 with taper shaft prop hub and Hegy wood prop. I was astounded to see that he took out the tracking error by using a shim made from nothing more than a piece of paper just slightly heavier than ordinary copier paper, between the prop and hub, spanning the space between two of the prop bolts. I believe it reduced the difference to less than 1/32" on a 72" prop.
I now have an A75 on my Piet and it has a flanged prop hub. Same problem... when I checked prop tracking at annual, the Culver wood prop was out of track by a bit more than 1/8". Using Jeff's trick, it shimmed out to nearly zero. Following that up with a DynaVibe balance and a small counterweight out in front, not only does the prop track almost absolutely true, the engine/prop combo is super-smooth. Makes a difference. PS, in smooth air and level flight in cruise, I could feel the very slight vibration when the prop was tracking with one blade 1/8" out, and that's with an engine that turns about 2250 at cruise. I don't know what that translates to with a shorter prop, 1000 RPM higher speed, and 1/4" out of track. Oscar Zuniga Air Camper NX41CC "Scout" Flying Squirrel N2069Z "Rocket" Medford, OR website at http://www.flysquirrel.net
