I have a 20ft '85 renken cuddy with a 2.5L OMC sterndrive, with the original OMC outdrive. The boat runs great with just me in it, top speed of 38mph at around 3700rpms (off my depth finder), " I'm a little ****" as soon as I get some people onboard, (3-4 more riders), I can't get the boat to...