I have a 1956 evinrude lark 30 hp. I was on the water yesterday after overhauling my lower unit and was not moving foward or backward while in either gera. I thought I may have messed up in the gear Dept. With the prop off I am able to engage into gear just fine. With it on it just slips on its hub. I took the hub out and the rubber is badly dammaged. Should I just get a new prop? Sorry for such a novice question.