High RPMs but low speed

[rickycobble]

I have a 2021 VF250 on a 25 ft pontoon. I normally get 40mph at 5500rpm WOT. Boat sat for three weeks in the slip and took it out this past Saturday. Could not get past 26 mph at 5500 rpm WOT. Is there anything other than spun prop or cavitation/ventilation that would cause this?

 

[99yam40]

fouled boat bottom or extra weight .
water getting into the pontoons ?
spun prop would mean high RPMs with little
forward motion
so would a damaged prop

 

[rickycobble]

Thanks. I talked to my local dealer and he suggested it could be algae build up. It had some build up on when I parked it three weeks ago and I did notice it had accumulated more when I took it out this past weekend. I’m having it cleaned this Thursday. I’ll report back with the results.