Kohler engine

If the Kohler is old ( K series), dump the new put in SAE30 or whatever Kohler says.

While ANY engine will run with ANY type oil in it, you'll get best results using whatever type the MFR recommends .Brand of oil isn't important, it's the 'spec' that counts.

Also if 'newly ' rebuilt, change the oil after say 50 hrs or whaterver the MFR says.

The biggest break-in problem people have with the K-series Kohler singles, is that they start them up and listen to them run, but don't put a proper load on them... hence, there's no significant combustion pressure to force the rings to seat.

I haven't done any lately, but 20 years ago, I built a dozen or so, including the 'somewhat stronger' K241 in my 109 plow-pulling beastie.  I did at least six 241's, several 301's, and a 341.

I built all my K-singles for my Cub Cadet hydrostat (WF, NF, and QL series) tractors... and my process was to start them up just long enough to get timing and carb set, then hop on and head down the street, to a hill, run them up to governed speed, and advance the hydro until the engine started to pull down from high idle to governed speed, then run up that (quarter-mile) hill... then drive back down (basically coasting, right?), then repeating about four times.  The return down the hill provided cooling time between 'pulls', but after four runs up the hill, I had seated rings.

Kohler K-singles don't have oil filters...  they just get changes.   I used conventional for the break-in run up the hill and back, then drained and put in 10-30 Mobil 1.  Aside from the fact that I beat the daylights out'a those motors, they all did fine...