2001 80hp four stroke Yamaha/ lower unit issues

[Jimmylarkin@gmail.com]

Was driving my boat at 75 % power and a loud thud and the motor was still running but the prop would not spin. Tried reverse and forward but nothing!!! I guess one of following.
1. Lower unit seized up ( seems odd as motor supposedly has 350hours)
2. Shift cable broke/ tried shifting and it felt same as always in terms of resistance
3. Shear pin broke( assuming that this motor has one) I did not hit anything that would cause it to break ie no logs etc.

After hauling boat out I tried to spin prop by NAND and it was very stiff / not sure if this means anything...

Any hints or suggestions greatly appreciated.

Jim

[robert graham]

Maybe you have just spun your prop, or the failure of the center rubber bushing between the inner hub portion and the outer portion with the blades...props can be rebuilt or a new one purchased....the rubber bushing is there to protect the gears and drivetrain during a prop strike...

[Jimmylarkin@gmail.com]

Robert thanks for the reply I turned the prop by hand 10 minutes ago and it is very stiff and you can hear / feel grinding.

[99yam40]

We can just guess at what happened, you need to take a look.

Drain the lower unit to see what the lube looks like.
Shift gears while moving prop by hand(engine off) to see what is happening
disconnect shift cable at motor and try moving shifter by hand

Drop lower unit and inspect the drive shaft

Let us know what you find

Edit
Just read your new post
sounds like gears had a problem if there is grinding
need to disassemble to see what happened

[Jimmylarkin@gmail.com]

I am gonna take it to the shop on Monday/ I could pull it apart no problem but getting it back together is another story .. Thanks