Lol, you got me. The RC Karma gods have already exacted their retribution on my engine for that attempt at humor.

As a first step, I replaced the Master Airscrew 18-6 with a Zinger 18-6 for an apples to apples RPM comparison.
The Master Airscrew 18-6 was turning 8,300 rpm. With no needle adjustments, the Zinger 18-6 maxed out at 7,400 rpm.

As I recall with the smaller 10" to 14" props, the Zingers usually had more bite than the Master Airscrew props..

As you predicted, changing props seemed to help the mid-range burble on the ground.
The Zinger hasn't been flight tested yet.

However, the Zinger did exhibit the "Porky Pig" sound a couple of times during slow transitions (see first video below).


Then while slowly decreasing throttle from full, the engine just died (first time ever!) as if the kill switch had been pulled (see second video below).
Then the engine would not restart, even using the tried and true Sea Foam as a starting fluid.


I have replaced the Bennet's kill switch. It seemed to test normal when off the airplane and without vibration.
The spark plug looked clean. I will try to get the engine started again tomorrow.

Any idea what causes that Porky Pig hesitation sound?
I'm wondering if it was an early indicator that the switch might fail, if it in fact failed.

Thanks again for all your help..