Nice pictures, the first thing that leaps out at me there is do I see green grass? In NY in November?
On the rocker shaft & valves I don't see anything obviously amiss. Do you?
A couple of little things:
I do see a little bit of carbon crust on the what I think are the exhaust valve springs. That's a sign of a some blow-by past the valve guides and valve stems. Pretty common in engines with lots of hours. In fact I've seen much heavier carbon buildup on old low compression engines that ran just fine. So that's expected and not the problem.
Hmm.....Is that wear on ends of the rockers where they push on the valves?? I can't tell if I am looking at wear or shadowing.....looks like wear. Again, consistent with lots of hours. Or they could have been made that way. If wear, one of them has a lot of it though I'm not familiar with that particular engine and that style of forked rocker to say for sure from photos.
But I don't see signs of anything that would lock it up. I didn't expect to.
On one of what I think is an exhaust (last photo, center) has excessive tappet clearance - but not as much as I'd expect if it would have if had struck the piston hard enough to lock up the engine.
Next move it it were mine would be to pull the plugs and look inside the cylinders. That might even be worth getting a borescope to look around. Price on some of those has come way down on Amazon. Some USB type are less than a head gasket. not I don't know much about them & not used one on an engine yet, but it seems better than pulling a head for no reason.
And that tool would give you a better view in the bell housing to see if anything came loose - like one side of the ring gear that several mentioned.
It's looking more and more like you will be dropping the pan.
rScotty
Yeah, it's been pretty mild here. I'll take it, although the ticks are out in full force when the weather is this mild.
I don't notice anything glaring, however it does seem that almost all of the rockers are nearly on the same plane. Tough to tell, I'll have to put a straight edge on it. The loader frame is pretty in the way at this point, but I'm only pulling the loader if I need to.
From what I know about this machine, it's never been apart. I was quite happy when I pulled the valve cover and it was as clean as it is, but yes, there's definitely some blow-by.
The rockers are definitely a bit worn, too. Again, I'm with you, don't see anything that would cause the machine to lock up. The head is coming off regardless, it needs to be redone. I get lots of oil leakage into cylinder 4, I'd like to get that taken care of.
Glad you noticed that last pic as well. There's also a small piece of maybe a shim or something that broke off and was sitting on the other side of the head. You can see it in the second to last pic on the right side.
I tried to look into the cylinders, the inspection scope I used wasn't small enough to really see what's going on. Again, with the oil leakage on #4, the head is coming off regardless. I'll put some bolts and washers in the block to hold the sleeves in, then see if it turns over. Worth a shot, but I doubt it at this point.
I still don't know if it could be a dislodged ring gear- the machine was down on power (not overheating, still full of oil) before I shut it off. There were no odd sounds or anything. It ran when I shut it off, turned maybe 1/8-1/4 of a turn with the starter the next morning and that was it. Locked.