RE: The Unofficial Outboard FE Tunnel Thread
your rite peter the guys running the ul-1 motors use 4s, for racing they use a 42 x 55 prop,fairly sure its a grimracer prop.
and i agree pranther 215 is to big for that motor, 438 or 440 would be a good start
did see a guy useing around a 638 on a vs1 with a ul-1 motor 4s 5200s,think he was getting low 40s with about 10 minute run time,will try and check that out later and report back
scott