40tlrx lower unit slipping?

[mudslinger]

Motor starts and runs fine at slow speed. Revving up to a moderate speed causes a noise and there is no increase in speed of the boat. The prop looks to be secure. Is the prop shaft slipping, is there a pin nearly sheared, stripped gears, etc? Thanks for any help.

[Ken]

mudslinger,
Sounds like the prop is slipping on the rubber hub insert - take it to a prop shop and have a new hub insert pressed in.
Good luck,
Ken K