Thanks Hobbsy,

It looks that propeller is a bit too "heavy" for this engine,
which seems to be mich higher-rpm-engine, isn't it ?
If I use the calculator of Pe, it gives that this propeller
have only 1.68 bhp, while the engine is advertised to
be able to deliver even more than 3bhp. It seems
I'm missing some point here; please clarify further.

Regards,
Nick