Hello new to the community. I have a 2011 craftsman with a kohler courage sv620s 210 22 hp. When started it would hammer like a rod was giving up. Same when revved up and under a load. Torn it apart and rod has wear only on the upper side of the main journal side. The cap has none whatsoever. The crank shows no sign of abnormal wear. Seperated the deck from motor to test to ensure it was the motor. Any known vibration problems? Junk motor and replace with Briggs? If so recommendations to what to replace with? Thank you in advance