I;m new to the gas/ 33% world and I now have two engines that are cranking 20 to 22 inch props. Both are second hand, even though the Zenoha has yet to run. Both came with some new props as well as a couple that have been opened up to fit. The other engine is an O.S 300 FT and the props that came with it are 20" APC props. Three of them were bored out to fit the crank, but it looks like a sloppy job and it also looks off center.

My quesion is two fold. First, can I use the cast in ring on the back of the APCprops to "find center" so I can bore and bush the prop to a known good center. Second. The O.S. comes wiht a drilled and tapped prop hub and washer for 6 4-40 screws in adation to the prop nut. The previous owner didn't use the 6 screws, but relied on just the nut. It this a problem.

Thanks,

Don