It sounds like you got the Tru-Turn TT-0105-A adapter for the Moki 2.1. I had the same problem as you and here is the simple solution.......................................... ..contact B&B Specialties at
http://bennettbuilt.com/page9.htm
Order the 13.4 mm drill bit and have them custom grind the pilot to fit the existing hole in the brand of prop you use (Mejzlik and Menz are 10 mm). This gives the prop shaft hole an ID of .527 while the Tru-Turn adapter has an OD of .525 for a clearance of .002, a very light press fit. The drill bit is $19.95 and the custom ground pilot is $2.00, a real bargain in my estimation as it allows a precision fit and it is very easy to use. Hope this helped.
John