Y'know, you're right! The prop on the Evolution engine is held on with a smallish hex nut, Metric, maybe 8mm.

You can use a proper sized hex wrench or an adjustable wrench, as long as it's a Metric Adjustable.

(That should start things going!)

The spinner is held in place with 3 Phillips head screws.

I must have been thinking of my Electric Rascal.

Thanks for bringing me back in line....