at this point, if you didnt need to add the right amount of oil fore it to show full, then i would just pull the engine, flip it over, remove the bottom sump and get a look inside. until you do that i cant see spending another minute or another penny messing with it until you are certain whats going on inside there. check for excessive play and movement in the rod bearings and piston as you turn the crankshaft without actually taking them apart
worst case is if everything looks ok, then you just have the cost to replace the gasket and oil seal, but at least then you will know for sure what you are dealing with
I feel like I'm in the Twilight Zone. I drained the oil, and popped the bottom off the engine, and there is no goo. No sludge. No paste. There was a surprising amount of oil still in the engine, which was upside down at this point, so pooled at the top of the engine. I dumped it out -- it look like used oil, nothing worse than that. Quite a bit,
That means, when I initially dumped the mower upside down, it didn't drain all the oil, or even close. In all fairness, I found an oil plug on the bottom, and if there is a right way to drain the oil, it would be via the removal of the oil plug. I did look for one, when the engine was on the deck, and couldn't find it. Must have been covered up. So, when I believed that turning the mower upside down would drain all the oil -- I must have been wrong.
I'm still struggling with my finding paste oil on the dip stick. And the dip stick itself was sticky -- like dried oil. I do recall, when first checking the oil, that getting the dip stick out didn't seem to require turning it. I imagined at the time that maybe the dipstick had been on there loosely, untightened. Then I decided: so what? Previous owner had been working on it. And went on. Loosened recently wouldn't have mattered.
However, if it had been on there loosely, all winter, then I guess the oil at the dip stick could be thick, but not the rest of it?
I feel silly for dragging you into my nightmare. I've never seen a case of me being so far removed in my thinking from what was, I guess, actually happening. Loose oil dip stick, just sitting on there, not tightened. All winter.
That's all I got. Dumbest thing ever.