Rod,
This topic has been discussed to death, but put a YS 110, Saito 125, Saito 120 with a 16X4 APC prop in your funtana and you'll love it. We have seen them with 2 strokes and they work but seem a little sensitive in torgue rolls and rolling harriers, and don't sound as good as a 4 stroke, TRing close to the ground.
Jim B