Mag Drop

The manual says to do these checks at 4000.  It might be interesting/informative to do the checks at the recommended rpms and compare.

hello Ray

it is important to do this as noted by Tyler at 4000 RPM.  Make sure that the engine is warmed up also.  The reason for this is to get some HP going and to check it at the lean burn area (mid range) for a better understanding of your fuel/spark working together.  

I don't know the engine type, 80, 100 or 115 HP?

A lean burn at the test point can cause a very high drop.  Be sure that the settings are correct for jetting and needle clip position.  Be sure that your prop loading is not too high or too low (overpitch/underpitch) as this can affect you also. 

Cheers