2002 MERCURY 90HP 2 STROKE EXHAUST SOUND ISSUE

[trent0416]

SO I WAS HEADING IN THIS EVENING OFF THE RIVER, AND THE BOAT OUT OF THE BLUE ACTED LIKE I HIT SOMETHING UNDER THE WATER. IT SEEMED TO REV A BIT AND MADE A NOISE, SO I BACKED OFF THE THROTTLE AND STARTED AGAIN. EVERYTHING WAS OPERATING FINE AFTER THAT, BUT WHEN I GOT INTO THE MARINA NO WAKE AREA AND IDLING ALONG, IT ALMOST SOUNDED AS IF THE PROP WAS NEAR THE SURFACE A BIT TO WHERE I COULD HERE A LOUDER EXHAUST NOISE LIKE IT WAS IN AND OUT OF THE WATER, BUT I WAS TRIMMED DOWN COMPLETELY. DEFINATELY NOT THE NORMAL. GOT BACK TO THE DOCK AND TRIMMED EVERYTHING UP, AND I SEE ZERO DAMAGE OR SIGNS OF HITTING ANYTHING, BUT THE EXHAUST SEEMS LOUDER EVEN WITH PROP COMPLETELY UNDER WATER. SEEMS LIKE MAYBE IT IS LOUDER FROM THE EXHAUST PORTS BELOW THE COWL? IS THIS ;POSSIBLE? WHAT COULD CAUSE THIS? ANYTHING I SHOULD BE CHECKING? THANK YOU IN ADVANCE

 

[Texasmark]

You may have got into some moss or a plastic bag causing cavitation/ventilation of the prop. Or you may have blown a seal between the powerhead and the midsection. Why not put it on muffs in the driveway and see if you can pinpoint the source of the added noise. Only places exhaust should be heard is from the pressure relief ports at the rear top of the mid section, and out the prop exhaust. Next pull the cowling/cover and check the engine while running for noise and water where it shouldn't be, like the exhaust manifold water jacket leaking.