Cub .099 What size is prop screw?

stevej Sun Apr 21, 2013 2:13 pm

I have a Cub .099 with a cross-threaded prop screw. Can someone tell me what size it is so I can buy a tap?

jjscott Sun Apr 21, 2013 4:12 pm

Steve: I'm almost 100 percent certain it is 5-40. 6-32 is too big and 4-40 is too small. The bolt threads on my .099 match the 4-40, so the pitch is 40. My taps and thread gauge are at my other house, so I can't get to the 100 percent mark.

I do have an .099 parts engine with a good crank and excellent cylinder with no damage. It's missing the n.v. and head and the big end of the rod is loose. Consider it if you can't fix your crank.

Jim