1988 Johnson 8hp wont pull. Is it seized up?

I've got a 1988 8hp that I just bought from my uncle for $150. He said it run a couple of years ago but has sat since.
The throttle can go from idle to full throttle in gear, reverse or neutral. It seems, I would think, that this may be my problem, safety limitations that I cant seem to find or correct that limits it from starting in gear and/or at full throttle.
The starter engages the flywheel but the flywheel doesn't move.
In neutral the prop spins freely. In gear however, it wont turn.....(maybe it is seized up from sitting without lube and heating and cooling and some humidity rusting the piston to the cylinder wall).

Any ideas? Any bets on what it is? Thanks in advance for some direction.

You can remove the spark plug and squirt some penetrating oil inside the cylinder. Put a steel rod through the hole, against the piston and gently tap with a hammer, sometimes the jarring can break the weld made by corrosion. Put it in gear and rock the propeller back and forth. If it doesn't free up, use some more penetrating oil, give it some time, try again etc...
You should be able to turn the motor over by hand with the propeller if it's in gear, there's no safety feature I've heard of that would prevent that.
Good luck!

I think there are safety features that prevent the motor being started in gear on this motor. The older outboards it's pretty obvious and on the inside of hood and moves in and out with the shift handle. On this motor, I cannot see any, but believe that it's there....somewhere. I can see on the recoil starter that there is a feature to prevent it from starting at high RPM, but I can't seem to find anything regarding starting it in gear.

I've begun to research the seized motor issue and appreciate your direction. If it is seized I hope it's not rusted in there too badly from sitting so long.

You won't be able to pull the rip cord or engage an electric starter with it in gear, no. What I meant is there will be no safety feature that actually stops the propeller turning with it in gear - as in If you grab the propeller by hand and torque it. If it spins freely in neutral and you can't get the fly wheel to turn by torquing on the prop (by hand) with it in gear - you probably have a seized engine.

Fill the cylinder with penetrating oil, give the top of the piston a few taps, it may click free and be fine you never know your luck.

Well, that doesn't sound fun ;-) But I kinda figured that might be what the story is. I appreciate your help.
The piston doesn't seem like it would be very easy to get to though the spark plug hole to free it. This might suck.

use a brass rod instead of a steel rod so you dont damage your cylinders. Is it easy to get parts for it? if so I'd pull the head and inspect the cylinders. It does sounds to be seized but try what the first guy suggested (With a Brass Rod!). Dont hit too hard but penetrating oild and some jostling up can work wonders!