Motor is a 115 Yamaha, 4 stroke, on a bass boat, starts and runs well under 4500 rpm. Once pushed above this level it runs well but seems to run hot, even though the gauges show the motor normal temp. Once the rpms drop down the engine seems to make noises like scraping noises. this only happens after running above 4500 rpm. Engine feels hot to the touch after. If I stay under 4500 rpm this does not happen. Can anyone help? Engine is only two years old with less than 30 hours on it. I just want some info before taking it in to techs. Thanks in advance for any help.
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