I just bought my 2012 Bennington 20sl with a 70 HP Yamaha. I took it out the other day for the first time with 7 passengers and it only ran 13 knots.Today I took it out by myself and it ran 16 knots with adjusted trim. The only problem I could see it that it only got to 4400 rpm at full throttle. I'm thinking I should at least see 5500 Rpm safely. Could it be possible that I need to get the throttle adjusted? Is the normal for a 70 hp? Any suggestions?