I have a 1990 17ft hydra sport bass boat with a 1990 150xp SLE Model on it. Just had it rebuilt last year runs great. It has a old style Raker prop on it and WOT RPM is around 4900 and 62 on speedo. My prop guy tells me these motors between 1986 and 1990 run best around 4900 rpm but this is not...