Join Date: Sep 2005
Location: New Westminster, BC
Thanked 587 Times in 558 Posts
Rep Power: 17
As important as horsepower is the design of the lower unit and the prop. A good 4 stroke 8 hp with the right prop for the boat will likely do the job for a boat of that size, though the 4 strokes are somewhat heavier. The 6 hp would probably do until you were forced to motor into a heavy headwind or large seas.
As for the "crack" in the paint at the hull/keel joint, this is not uncommon on boat of this vintage and simply requires careful inspection and/or as Seabreeze suggests resealing if there are any leaks or seepage.