ORIGINAL: snoozer
Oops, I unintentionally mis-stated my prop size.
I have a MA 10X5 prop on the engine.
Snoozer,
That is quite a bit more probable.
However, Master Airscrew limit the RPM of their props to 160,000/diameter in inches, which for a 10" diameter means 16,000 RPM.
If you run that prop at this RPM, or fly it (which causes RPM to increase due to unloading), you would be risking disaster from a thrown blade...
I agree a warm plug, such as the OS #8, Enya #4, Novarossi C-6S, or K&B-1L are appropriate.
The lowest cost plug is the TowerPower, which is very similar to an OS #8.