2004 four winns 8.1 volvo with 90 hours. We had a problem with the starter and a mechanic replaced it. We took the boat out and it fired up great took a little bit to get up to 150 degrees but never did get to 175. Not the highest rpm is 3600 and takeoff seems slower than before. Max speed is in the 40's with the 34-3600 rpm. I changed fuel filter and still does the same. The gas is down to 1/4 tank and nothing else has really changed. Idle is good and smooth I have not tried to rev the engine in nuetral. Is there a switch or something that might have been hit when replacing the starter that would cause this and what should the volt meter read when running. Volt meter reads 13 and a shade under on the dash. What is the best way to hook a volt meter to see the actual charge volts? Also cleaned the screen for the air intake.