Small Engines (Lawn Mowers, etc.): Kohler magnum 16, twin cylinder engines, full throtle

Question
My gravely tractor has a kohler magnum 16 motor that is not running correctly.  When idling it has some sort of miss on one cylinder.  It pops through the muffler (not every cycle, maybe every tenth rotation).  When I run the tractor at full throtle the pops get more noticeable.  If I engage the mower deck they tend to quiet down considerably, but they do not completely disappear.  I suspect this may be a worn or defective exhaust valve.  It only happens on the left cylinder.  The fuel is good, the carb is clean and adjusted.  The numbers are spec #24544 and the serial # 1630711706.  The tractor was purchased around 1988.  It is a gravely professional 16-g four wheel tractor.  Before I remove the motor I want to confirm the exact cause of the misfiring.

Answer
Hello Mark:

Sorry for the Delay. I had to Purchase a New PC and then Switch my Files and Records from the Old One. Also this New PC is Giving me Problems and These are Causing me to Go Offline for No Reason. This is Slowing my Response Time. There are Glitches in it. Thanks. Some of the Older Model Kohler Engine had Solid Tappets and Not Hydraulic. The Problem May be a Valve Seat having a Burn in the Seat of the Valve Face or a Burn on the Face of the Valve Seat. Set the Engien at TDC on the Left Cylnder and Check the Valve Clearance. The Gap Between the Valve Stem Top and the Tappet should be Set at the Following. The OEM Suggest that Both Valve Clearance be Set at .004in. **I Do Not Use the Setting Called for by the OEMs. I have Found that the Following Works Best. Remove the Valve Cover (on the Dead Cylinder for Twin Cylinder Engines). Set the Cylinder you are Setting the Valves on to Top Dead Center (Both Rocker Arms will have Play in them when the Engine is at TDC) When Setting the Valve Clearance. Now Loosen the Valve Adjuster Locks and Set the Intake Valve Clearance to .004in -.006in and the Exhaust to .007in - .009in. I have had Better Performance Out of the Mowers and Less Burnt Valves Using these Settings. Be Sure the Piston is at TDC on the Compression Stroke.**  If this is Not an OHV Engine, then the Valve has to be Removed and the Valve Stem Tip is Slightly Ground Down Until the Proper Clearance is Achieved. If it is an OHV Engine, then it Most likely has Hydraulic Tappets. From your Description I Suggest you Check the Valve Clearance or Reseat the Valves. If you Hit a Snag or this Does Not Correct the Problem,  I am Here if You Require More Assistance. Hope this Helps. Let me Know What Happens, Please. May the All Mighty Bless You and Yours. Thanks.

Good Luck

Respectfully

John

PS: I am Allowed to Answer 10 Questions a Day. If you See I am Maxxed Out, then Try Submitting your Question at or Just After 8pm EST (US). My New Day Starts then. Thanks.

Respectfully

John