May be my imagination, but after running both my engines about 120- 140 hours or so each summer season since new, I believe I am hearing a change in the tone(s) when running at my range of cruising speeds of about 3400 to 4000 RPM. It "seems" (key word here) that tone on one (or both) is slightly deeper or throatier than before. I have always believed that machinery talks, if we listen. In this case, I don't know what it might be saying -if it is not my imagination.
Both engines are running well though out their RPM range. No indication of loss of power or hesitations. They are idling a little lower (500 RPM) on start but never stall. Lower unit seals and water pumps on both engines were replaced last winter. The heads have never been pulled for any reason. No other changes in performance or indications of something different have been observed.
Is there anything that in the path of the exhaust system that changes with age or use? or are there changes in the combustion chamber that would affect the sound of the exhaust?
Any other suggestions other than 'you are probably hearing things "
Thanks in advance.
Both engines are running well though out their RPM range. No indication of loss of power or hesitations. They are idling a little lower (500 RPM) on start but never stall. Lower unit seals and water pumps on both engines were replaced last winter. The heads have never been pulled for any reason. No other changes in performance or indications of something different have been observed.
Is there anything that in the path of the exhaust system that changes with age or use? or are there changes in the combustion chamber that would affect the sound of the exhaust?
Any other suggestions other than 'you are probably hearing things "
Thanks in advance.
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