Would like to upgrade my 1978 8Hp Johnson. This motor measures 17" and is on a Starcraft 14' Alum V. The transum measures 15". So can I assume I need a short shaft the will measure between 15 & 17 or should I stay with something that is not longer than 15? Also any suggestions on a 15 or 20 hp I might want to look at, either new or used and of course never abused. Thanking all responces in advance.
