I’d been having issues with engine, while mowing, and about 1+30 into the mow, engine was / is losing power and starting to back fire (unclear to me whether through the Carb or Muffler). My Brother (via long distance call said it sounded to him like I have a Valve “Acting Up,” rather than a Carburetor Issue). Yesterday, after reading Kaw Service Manual, I looked into adjusting valves. Started with Cyl. # 1, got what I believed the Cyl. to be at TDC & set the Intake to .006. Went to Exhaust, Clearance was NON-EXISTANT, so proceeded to adjust via the Manual, and Exhaust Valve NEVER FREED UP. Moved Cyl. OFF TDC (Don’t know how much / far), and Valve moved to where there was some Clearance, after having none. Scratched my Head, moved Cyl. #2 to TDC, and adjusted both Valves to .006, WITHOUT ANY DIFFICULTY. Moved Cyl. #1 BACK TO TDC, proceeded to Adjust those Valves again. Adjusted Intake with no issues, but Exhaust STILL WILL NOT ADJUST OUT OF A “NO CLEARANCE” Condition. Outside of taking the Head Off and examining what’s going on under there, does anyone have any suggestions of what I might try to free this valve up and adjust while at TDC. I’m certainly not a “Professional Mechanic,” and would appreciate all the feedback / recommendation(s) anyone can offer. Next Stop just might have to be to my “Over-Priced JD Dealer,” and a 2 - 3 week back logged visit. Thanks for your Responses.