Small Engines (Lawn Mowers, etc.): erratc idle, carburetor body, adjustment screws

Question
Help please. I have a 2001 Scotts by John Deere S1642 riding mower that has always ran well until recently and today just won't start. It is 33 degrees out if that matters. I have noticed that this past cutting season my tractor at fast idle would have an erratic idle.  It would race up and back down but it has been doing that far more frequently and recently started racing higher and then dropping lower until it stalls out.  Two strange things that I noticed is that at a slower idle line 20 to 40% it would idle nice and smooth and if I start it once it is warm with the choke fully on it would run rough for a few minutes and then smooth out and it would stay running  - I know that is not right.  Please offer help as to why the problems could be and what needs to be done and the carb adjustments...   Many thanks.  Brian  

Answer
Hello Brian:

The Carburetor Requires a Good Soaking and Cleaning.  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, Float Pin, 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. Install New Parts if Required. You can View a Breakdown/IPL of the Mower at this Site Addy, http://jdpc.deere.com/jdpc/servlet/com.deere.u90490.partscatalog.view.servlets.H... and Enter the Model Numbers and Click Find. Then Select the Sectional File. Then Select the Section of the Mower you Wish to View Online. 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. Have a Happy Holiday Season and May the All Mighty Bless You and Yours. Be Safe and Happy. 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