I just bought a new Rinker 232 with a 350MAG MPI Bravo 3 and 28 pitch prop. I was told this boat would do 55-60 easily. After 18 hours of break-in, it will only do 45mph at 4400rpm. The dealer did engine diags and says everything is fine. The dealer told me to use it for another 10-20 hours and see if it gets better. Am I wrong to think something is wrong?