I have a 90 hp merc ser# A190854 with a quicksilver 48 72500 a5 21 pitch prop mounted on a 15.6' glasscraft bass boat which is rated for max 110 hp. <br />1st issue - the boat planes out between 2500 nd 3000 rpms and when up to about 3500 it runs great for about 5 minutes and then the rpms go...
