Re: 1961 sea king 12 ft alum. semi-v...west bend 18 hp...good mates?
Eighteen hp is probably too much for a 12' tinny, Dave.
Also, though the West Bend was a good engine in its day it is very obsolete in terms of getting service or parts.
I would look for a 9.9 or 10 from a major brand for that boat.