I got the shop manual and I have flipped through it. All kinds of diagrams on how all of the parts go together but no new information on diagnosing the issue. Fiddling with the blade clutch cable is still my only course.
I fired up my mower today and everything worked great at first. When I engage the blade the engine revs up and when I disengage the blade it revs back down. As I continued to use it the rev up and down got progressively slower until near the end it would NOT rev down after disengaging the blade...