Kinda confused here. Put a new backh20 prop (9x6) on my GD lt before September teal. ran great with it. Just changed it out Thursday. Had worn it down to 7.5". Put a new GD prop on and it's like the motor can't spin it. Really gives the motor trouble at high rpms in the water. Noticed a lot more cup in the GD prop over the backh2o. Wondering if yall notice a negative difference in performance when you put on a new GD prop.

Old prop vs new prop

That prop looks to be 2 or 3 inches larger than the old one....you sure you got the correct new prop?

It had 9x6 stamped on the hub. Measured it and it 9" across. Only thing that could be wrong is it could be a 9x7 they mis stamped as a 9x6?

No, it is 9x6. Just has a lot of cup when it's new. What size motor?

25 kohler

You should be able to turn that prop. I had a similar experience with a 23. I have a GD prop that is still 9" diameter with a slight wear on cup and I can turn it 3910. I put a new GD 9x6 on thinking it would maybe take 100 rpm but it dropped to 3600 or so at about the same speed. I put my old prop back on because it carries a load better. You don't have that option because your old prop is too far gone. What rpm can you turn the new prop?

No tach on the motor. Haven't put one on it yet. I can tell it's not what it was before though. Really need to get around to installing a tach on the motor.