2020 AR195 top speed lacking

[bbrown58]

Curious if anyone can’t point me in the direction of what else to check. It seems everyone with the AR195 is topping out around 46-49mph. My boat will not go above 35mph. It is running WOT at 7450 rpm which seems to be on par with Yamaha 7500 spec. I just put new iridium spark plugs in it. Last year it got the solas impeller, lucky cone and upgraded air filter. I run 93 premium fuel and I have checked the speed with phone gps it is topping out at 35 mph. Located in Ohio so altitude shouldn’t be a factor. I wet slip the boat can the sludge really cost me close to 15mph top end? Any thing else to check?

 

[Mesa50]

Could be cavitation. Check the silicone seal around the intake grate. Also check the clean out port. Sometimes the o-ring wears and too much water flows past plug. The single engine Yamaha boats are also sensitive to weight load. 5-6 people with gear will drop the top speed. Leave everyone at the dock, and do a speed test.

 

[bbrown58]

Thank you! I am leaning towards your first guess. Ski rope got sucked in about a month ago luckily I shut it off before it got sucked in to the point of stalling out. Was able to remove the rope through the clean out but I have noticed pieces of white silicone peeling off in 2-3 inch long pieces. Unfortunately I wet slip so I can’t fix it but I have 5200 marine silicone sitting here ready as soon as I pull it out for the winter. I will trailer it to test it out and let you know in the coming weeks. 35mph was with me on board only and 40% fuel. Spark plugs just changed. And I changed th o rings on that clean out plug last year.