i have a cub cadet with the 18 hp Kohler Courage SV541 single cylinder powerplant that is giving random cranking problems. on some occasions-but not all- it will stop on the compression stroke. i can pull the plug and get it to spin again, then replace the plug and most times it will go ahead and crank. i suspect that the culprit may be the compression release, but unsure because of the fact it only does this sporadically.
any input would be greatly appreciated. 

If your engine stops just past the compression stroke, when re-starting, it'll have some 
momentum when it hits the compression stroke.
 
Pull the valve cover and inspect (adjust if needed) valves.  The exhaust valve should have a slight bump
when cranking.  No bump indicates a bad compression release.
 
IE:
https://video.search.yahoo.com/search/video?fr=mcafee&p=automatic+compression+release+22hp+kohler&type=E210US1498G0#id=1&vid=8fed4fbc07d37700d6b3eaec54441014&action=click 

thanks SRT i will try that.
thanks for the info