Quote Originally Posted by chrisag View Post
Just a thought... has the accuracy of the tacho been checked...
This is good advise. Analog (needle) tachometers are notoriously inaccurate over time on these engines. The Rotax tach I had in the yellow plane was reading 250 rpm low when I replaced it with a digital unit.

I would try to borrow a TinyTach from somewhere so that you can at least cross check your needle tach.