New Prop Spinning under power on 2001 Merc @

[soulfisher]

I have a new prop on a 2001 2stroke Merc 25HP SN# OT186630 The old prop spins a little bit but not as much as the new one. I believe it is because the old prop has very little cup left. Is there a rubber boot inside the motor that needs replaced or something? Thank you.

[JOE54]

there is no rubber clutch in gearcase , describe spins do you mean it slips /cavitates , props do spin/rotate thats how they propell the boat

[soulfisher]

Seems to be slipping to me. The old one does it a little bit but not as much as the new one. I'm guessing the new one does it more because it has way more cup to it. Thank you

[JOE54]

more cup should help with slippage

[soulfisher]

yes sir that is why I upgraded but it seems like it is slipping internally. both props are identical in size and pitch.

[JOE54]

possible internal gearcase problem

[soulfisher]

ouch. Thanks for you suggestions

[JOE54]

im sorry but its what i do

[soulfisher]

Understand and appreciate your time. Can you tell me what a used lower unit is going for these days and are they hard to find? thanks again.

[leonreno]

Do you have tachometer on this boat? If so then what are maximum rpms you reach? And max speed? If not, consider buying a Tiny Tach to read rpms, kinda important when trying to determine prop problems/performance.

[EuropeanAM]

Might also help to know what your original prop was (part number) and the part number of the prop you installed.