Hit it with some PB Blaster to break down the rust, and get it freed up good, dry it off, (high pressure air works good for that.) then hit it with some DRY lube. Graphite powder, or something similar. That'll solve the problem for quite a few years.Thanks for all your quick responses. PA318Guy and Alien5044 nailed it. Starter spins but doesn't engage. One drop of lube and a little pry to pull out the starter shaft one time and it's looking good. I should probably remove the starter and clean the shaft as you suggested to resolve this a little longer term.
Valve clearances are on my list next time the carb is off.
He has a Kohler one lung. It isn't OHV, so, procedure is a bit different.It's not that hard