Sorry, I should have been more clear, it's not the starter cover, it's the sump cover on the block.
 
Mod 20S232-1246F1

You simply have rust on the crankshaft preventing the cover from coming off.
 
Push the cover back on fully and with some sandpaper (maybe 120 grit), polish the shaft(especially close to the sump cover) until shiny steel.
 
It'll come right off.  A little lube on the shaft wouldn't hurt either.
 
 
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Yes, that did it.
 
thanks

Yepper. 
 
Also, Pay attention to the oil pump and oil pump shaft when re-installing the cover.

The engine looks reusable except for the cylinder. After honing to a good crosshatch there are still spots I can feel easily with my fingers. Mostly where the rings sat for a while with water in the engine. I assume that means it isn't usable without boring it out? Are these worth boring out?

doug2500
The engine looks reusable except for the cylinder. After honing to a good crosshatch there are still spots I can feel easily with my fingers. Mostly where the rings sat for a while with water in the engine. I assume that means it isn't usable without boring it out? Are these worth boring out?

 
Which engine?   
 
I thought the 18HP mower was fine..
Or is it the 10HP engine?  If so, please post a model # for the machine in question..(Always actually)
 
 
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The 21 HP engine on the mower is fine, everything works. The 10 HP engine from the sawmill is the one I'm working on now. The cylinder has some damage from the rings rusting against the walls I think. There was a lot of water in the engine. It's a Mod 20S232-1246F1.
 
 

With the old rings in the bore, where the damage is, can you see light thru there and if so,
get a feeler gauge in there? (you shouldn't be able to get one in).  A ring END GAP measurement
of the old rings be nice to know (measured about .5 - 1" down in the bore.
 
Ok, oversize piston and rings  (.020"  over) are available but ain't cheap(plus machine work):
https://www.partstree.com/models/20s232-1246-f1-briggs-stratton-horizontal-engine/camshaft-crankcase-cover-crankshaft-cylinder-lubrication-operator-s-manual-piston-rings-connecting-rod-warning-label-3/ 
 
For where you are now, re-boring / rebuild sounds a bit expensive.  
Depending on much the cylinder leaks with new rings, right now is a crap
shoot.  
 
Rings and gasket are not terribly expensive.  If mine, I'd re-ring and seal it up..
 
You can up to 20% leak down and still have a good runner..  
 
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 The head, if not warped, IF PARTED OUT, would go for about $50.00 alone, sooooo...

Ring end gap 0.014" snug.
 
There's only one spot where you can see like 3 tiny pinpoints of light. It would line up with the top ring at the very bottom of travel. No way a feeler gauge or anything else would get in there.
 
I have some good photos, but can't remember how I sent you the last ones.

I'd bet it'd run pretty good... Go for it!
 
 
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