Ive got a 3hp twin evinrude 1965 model that I use on 10 and under lakes. They work perfect for slow trolling, just make sure the water pump is good. You won't see any pee or steady discharge, just a good mist. It moves my boat pretty good even with 2 adults and 2 kids aboard. Worth? Depends, Ive seen a completely refurbished one list at $495 and used ones sell between $25 and $250.