Massey Ferguson 65 seized engine multi-power question

Looking into the possibility of getting a Massey Ferguson 65 unstuck. I need to look at it closer to answer any replies, but I seem to remember this running when it was parked, and I think the radiator was leaking and somehow it must have gotten rain water down the exhaust and seized the engine. I think this has the multi-power feature, and it has the high ground clearance. I haven't really looked at this for a few years, and it has probably been sitting for 10-15 years. It was my dad's who passed away, so I don't have anyone to ask any questions about it, just mainly going on memory. I'm wondering if there is a way to spin the pto to try and unstick the engine or would it have to be tore into?Emails, texts, or calls are ok. 314-three-nine-7-72-7-eight. Located in Southern Missouri.

It really depends on how bad it's rusted up. If
it's been sitting with the exhaust open to rain
for 10 years, good chance it will need to come
apart.

Didn't say if it was diesel or gas, but if you can
get the plugs/injectors out, take a peek inside
with a flashlight, see if there is evidence of
water damage, then make the decision to try to get
it turning or take it apart.

Take a look at the oil too, pull the drain plug
and see if there is water in the bottom. If just a
few drops, put the plug back in until you try to
break it loose. If it's full of water, might as
well start taking it apart.

If the oil looks good, and the cylinders are
somewhat clean, put some penetrating oil in each
cylinder, let it soak for a few days. Might even
pull the valve cover and see if any valves are
stuck. Gently pry down on each one to see if it
will move. If some are stuck, remove the rocker
assembly before trying to break it loose. Any
valves that stay open will need to be broke loose
before turning the engine! It will not hurt to
leave the rocker assy off while breaking the
engine loose.

After a few days soaking, try hitting the starter
with a good hot battery. It may not spin through
on the first try, just keep hitting it, watching
for any movement. You may have to recharge the
battery and wait another day, try again. Be
patient and keep hitting it with the starter. I
would not try any other forceful methods though,
could break a ring land or do other damage.

Hope you get it running! Let us know.

You can try the PTO when in engine drive but I doubt you will have any luck unless engine is not stuck badly. Probably have better luck with the starter removed and using a pry bay on the ring gear. Since it has Multi-Power towing is out.

Pull the cylinder head and see what the cylinders
look like. If you have sleeves they probably need to be replaced. Hal

I would try to manually bar it over from the front crank bolt. Try both directions. You may need to use ATF in the cylinders to help loosen it up. Patience is the key. I also removed the head and used a 4x4 and a 32 oz. ball pien for days on end because I didn't want to break rings. Mine runs well today without using much oil.

I appreciate the quick feedback. I forgot to mention this is a diesel. I had success getting a Chevy 5.7L unstuck that was seized up due to water leaking under the hood, sitting on top of the breather, and running down through the throttle body. I used ATF, diesel fuel, marvel mystery oil, and a ton of PB Blaster in the thing and eventually got it unstuck by spinning the flywheel. Once I got it going, I never had any issues with it. I've never messed with these old tractors before so this is a learning experience.