2005 Triton TR21x Prop

[Schwackdaddy7]

I have a 2005 Triton TR21x with a 2020 Mercury 250 Pro XS Four Stroke. I was running a 26 Tempest Plus which would push me at 76-77 GPS/MPH (tournament load) at 5900 RPM. I threw a blade and purchased another 26 Tempest Plus and I have lost almost 10 GPS/MPH. I was running down the lake yesterday opened it up and at 5950 RPM I got 64.5 GPS/MPH. I checked the slip calculator and it’s at 21.68%. Want my speed back and any help is greatly appreciated.

[Pulsare2020]

I assume you already checked all else like total load, jack plate height, transducers, etc. Since it is turning the same rpm, I doubt your WOT has changed unless the prop has more pitch and more slippage. Either way, 10 mph is a lot to lose from the same prop, with the same pitch. If you are certain it is the prop, I would call Mercury and tell them what happened and they might ask you to return the prop so that they can inspect it to determine if it is within spec. I had a friend that had a similar issue with a Mercury Racing ProMax prop ( but not close to 10 mph) and Mercury Racing asked him to return it, and they stood behind their product and told him what they found wrong with the prop. They corrected it and sent it back to him and it performed as everyone expected (I think it gained 3 - 4 mph).

[Schwackdaddy7]

I had Phil’s Prop Shop tune the prop to factory specs after purchasing the prop. Thought it might be out of tune and that’s why I lost the speed. I also have a Bobs hydraulic Jack plate and have tried playing with the height of the motor.

Thank you for the idea. I’ll contact Mercury and see what they think. I actually was going to buy a 27 tempest but really don’t want to waste a bunch of money if no need.