Wittkopfishing

Update. I took the boat to the lake for the first time in a while today. I swapped out my existing prop for my backup. No luck, was still getting the same sound from the motor. Interestingly, I put the boat back on the trailer and when I gave it gas, the motor sounded totally normal, even with the cowling off. Not sure what to deduce from that, but it seems like the noise chance only happens when I’m actually running.

Thanks for the thoughts. I have a spare prop that I could test. I had a similar thought because I had been running my boat through some vegetation and thought there might be a bunch of weeds in the prop, but I pulled it off and wasn’t anything in there. I might as well switch over to my backup prop and just see what happens. On the trim, no I have a standard trim setting that I always use and hasn’t changed it between the last time the engine ran normal and now. I’ll recheck the prop this weekend.

No, it’s a two stroke and just uses mixed gas.

I have a late 90's Evinrude 30 HP outboard that has been running like a top for the last couple years. I was on a fishing trip recently and during the third day of the trip, I was on plane and it seems like my engine was louder than normal. I didn't think much of it at first, but then after fishing for a bit I went to run again, and upon acceleration there is was noticeable pitch change. Seemed like as the boat would begin to come out of the hole, the pitch of the engine sound audibly dropped and got significantly louder. I attached a video below and you can hear the pitch change at about the 5 second mark. I was hesitant to run it very hard and risk any damage, but it seemed to perform fine, other than the noise. I could get on plane and sustain top speed as normal... was just loud. My assumption is that there is an exhaust issue (gasket or something leaking under pressure) but wanted to see if anyone has ever experienced this before I take it to a mechanic. Any help would be appreciated.