HorseFixer 2,012 #1 Posted April 5, 2009 I called my local Kohler dealer on my K-90 and the spec number traces back to a K-91 and When my motor doode gave me the extra gaskets back in the gasket set box part # 46 004 01 it traces back to a K-91 also. I know the k-90 is 3 1/2 hp and the K-91 is rated 4 hp but what is the difference in the other parts like pistons, rings, cranks, etc? Do these parts interchange? Since the K-90 is discontinued there is like no support for this engine whatsoever. I have a couple more K-90's to refresh and I would like to save a few bucks doing them myself at least the Assembly part. The machining I will sub out like cylinder boring and crank turning. Does anyone have an answer on this? :omg: Share this post Link to post Share on other sites