My son (Skydiver77) bought a 14' Starcraft Aluminum boat with a super long shaft 9.9 Yammie. I got the transom built up to the correct height, mounted the engine and the sucker will not get out of its own way. I found out the engine is a sailboat engine after the fact and designed to push heavy rigs. After he bought the boat, I've put over $300 into getting it ready and now have this problem. I've never owned a small 4-stroke but this one doesn't seem bo be turning over 2000RPM. Anybody have an idea re: prop selection or what else can be done reasonably? The engine looks new inside and out.