1990 froze up/seized While running

[reimelss]

I'm trying to keep the faith here but am afraid to have this answered.
1990 Mercury 115hp 2-stroke
While on the lake I was having some shifting problems and would hear a slight tick/knock when I let off throttle.
On way back to dock it felt like a plug fouled and the power died a little bit...then power came back and boat was on plane whe I heard a "pfffftt" and he engine died. It wold not turn over with key or manual rope.
- Oil was good/full
- water was pumping
- temp was below 140
Boat was running great besides shifting issue.
I know I have should pull the lower unit and see if the motor turns with out it on, but i want to see if anyone wants to weigh in on this, given the symptoms

 

[1nebel0]

Re: 1990 froze up/seized While running

Pull the plugs and try and turn it over...if it doesn't then pull the lower...let us know what your find...if there is any metal on the plugs motor is toast but let's see first if it will turn over....first things first.....

 

[reimelss]

Re: 1990 froze up/seized While running

ok good news.
- no shavings on the plugs...oil visible around the base of the plugs (at least i know its getting lubricated)
- removed the lower unit and was able to turn the motor over

The prop spins but it looks like the shaft is frozen.
I have the same lower unit in working condition that ill probably swap it out with, BUT the spare is regular shaft where as the one that seems to be fried is a long shaft.
Am i able to pull the long shaft out and swap it with the regular shaft?
any pointers on removing it?