Small Engines (Lawn Mowers, etc.): Sick Kohler, grass clippings, adjustment screw

Question
I have a Craftsman Rider - purchased probably about 10 years ago.  Since day 1 - when I go to dump grass clippings and leave the engine running - it starts missing and running rough - almost like it's vapor locking.  The mower this year has starting the missing and almost dying while cutting grass and the engine is under load - which it never did before.  I checked the fuel cap vent, replaced the fuel pump, replaced the fuel lines, replaced the air cleaner - disassembled the carburetor, cleaned, and reassembled.  I tried to get a carb kit - only to have the parts place tell me that the carburetor does not show to go on the engine. It came straight from Sears as it is now and has never been worked on.  The engine Model is CV15S, Spec # 41508.  The carb has numbers of 1205368, C128051, and 53G on it.  The carb has no low idle adjustment screw.  Sometimes when it starts missing - I can give it a little choke and it runs better.  Where do I go from here?  The repair shop said it would be a month before they could even look at it.  I called Kohler and found the right carb kit number - 1275727-S.

Answer
Hello Bill:

1- Have you Checked the Carburetor Shut Off Solenoid? If the Solenoid is Not Operating Properly, you will have the Problem you Described. The Following is an Instruction File I made for this Problem. Any Input is Appreciated. **Check for Current/Voltage (10.5 VDC Minimum) to the Carburetor Shut Off Solenoid. If the Carburetor Shut Off Solenoid has Current, then On Some Solenoids you can Remove the Needle and Replace the Solenoid to Test them. ****PLEASE DO NOT OPERATE THE MOWER WITH THE SOLENOID BYPASSED IN THIS MANNER. THIS IS "ONLY" FOR TESTING.**** For Others, Remove the Carburetor Solenoid and Go to the Hardware Store. Purchase a Bolt of the Same Diameter and Threads.It Needs to be 1/2" to 3/4" Long for the Horizontal Mount Solenoids and 1/4" Long for the Vertical Mount Solenoids. Put this Bolt in Place of the Solenoid. If this Corrects the Engine Problem, then Replace the Solenoid. ***NOTE: THIS IS FOR CHECKING THE SOLENOID ONLY I NEVER SUGGEST YOU OPERATE THE ENGINE WITH THE SOLENOID OUT OF THE CARBURETOR EXCEPT FOR TESTING PURPOSES*** Sometimes the Plunger is Moving, Just Not Far Enough to Allow the Gas to Enter the Jet.**  2- If the Carburetor Solenoid is Operating Correctly, then Soak and Clean the Carburetor.  The Following is a General Instruction File for Carburetor Cleaning. Even though the Carburetor Looks Clean, the Internal Passages May be Restricted with Varnish that Gas Causes to Build Up over Time. I Suggest you Make Sure the Gas is Free Flowing to the Carburetor Inlet Port. If the Gas is Free Flowing to the Inlet Port, then  **Remove, Disassemble and Soak the Carburetor Overnight in Carburetor Cleaner (I Use Gunk). I have Found that Most People can Use a Breakdown/IPL and Disassemble the Carburetor Enough for Proper Cleaning. You Only have to Remove the Bowl (if Applicable), Float Pin (if Applicable), Float (if Applicable)  and Needle Valve and Any Adjustment Screws that Go Into the Carburetor Body. The Welch Plugs Do Not have to be Removed. Then Soak the Carburetor Body and Parts in a 1 Gallon Can of Gunk Carburetor Cleaner Overnight. The Can has a Parts Tray Inside it for the Small Parts. Once the Carburetor and Parts are in the Cleaner, you can Replace the Lid for Safety and to Prevent Accidental Spillage. Then Blow Out the Passages with Compressed Air.*** (Do Not Use High Pressure Air for the Zama Carburetors, they have Check Valves for the Primer and these are Usually Blown Out of the Carburetor if Not Careful. Allow the Zama Carburetor to Set on a Drip Pan and Dry)***. Install New Parts if Required.** You can View a Breakdown of the Engine at this Site Addy; http://www.kohlerplus.com/login.asp and Select Enter as Guest. Now Select the Thumbnail of the Engine Catalog you Wish to View. Select the Command Single Thumbnail. Then Select the CV15 File. Then Select the CV15-41508 File. Now Select the Fuel System Folder. This has a Breakdown of the carburetor that you can Use to Assist you if you Decide to Soak and Clean the Carburetor yourself. 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