RE: 35GT prpellor Question?
Skillet,
This prop size is in the range recommended for the 26 cc engine.
Your engine will do much better, if propped with an 18x11, 19x9, 20x8, or a larger prop.
The technique would be to drill the bottom part of the prop to the required size (the hole does not need to go all the way through).
The shaft thread itself is 10x1.0M; not the thicker part.
EDIT: Typo.