Rebuilding 23hp Kohler thread tractor talk....

Just want to throw my experience with my 7000 series on my 2015 cub cadet xt2. So I read the engines owners manual as the dealer stressed maintenance had to be followed for warranty. Well iirc no break in hours were listed other than 100 hour oil change intervals if conditions allow. I happened to see a line stating that the filter should be prefilled once, and oil allowed to absorb into the media then installed. 100 hours arrived collected the oil, and a Kohler oil filter. The oil filter package said nothing about prefilling the filter, nothing! Consulted the lawnmower parts people, and others about whether or not it's necessary. Universally everyone shrugged their shoulders and said it's up to you, but nobody does that. So it was end of season, so I changed the oil WITHOUT following the manuals instruction to prefill the oil filter. Cranked the engine after changing oil, and mowed the yard. Upon shutdown a massive backfire...what...???? It's a brand new mower and hadn't done that pre oil change. Was worried, but... The shutdown backfiring occurred thru the next season, and more worrisome was oil leaks started from the valve covers.
So, the next oil change interval arrived, time to change the oil & filter. Put the filter wrench on the filter, and applied leverage causing the body of the filter to twist into a spiral form crushing it. Had to drive a screw driver into it to get it off. This oil change I prefilled the oil filter, re permatexed the valve cover gaskets. Since that second oil change no backfires, and no oil leaks from the valve covers. FYI

You have a Courage engine.
Valve covers leaking is a common problem with them due to the drain back design. Kohler has a fix for it. A plate that directs oil back towards the engine.

Backfiring Kohlers when shutting down is also normal. It may do it. It may not. Some say that shutting the engine off at about half throttle helps.

Pre-lubing the filter. Never did it on a horizontal oil filter. Just started the engine and let it run a minute then shut it down for about five. Engines with vertical filters. Most of the time I will fill them with oil before installing. Especially on a diesel engine.

Most likely you will eventually get the Kohler smokes. That is when it belches a cloud of smoke on start up. Again. Normal Kohler behavior.