Small Engines (Lawn Mowers, etc.): tecumseh tvt 691, carburetor body, internal passages

Question
above engine was surging badly and would run only on full choke.  I rebuilt carbs with the following: Removed welch plug and cleaned idle ports.  New plug seated and sealed with nail polish (as per factory manual)new emulsion tube o-rings, new bowl gasket, new needles and seats and solenoid gaskets.  Synchronized carbs.  Started engine and it ran great, smooth and plenty of power.  Mowed grass for 45 minutes and never missed a beat.  Shut it down and changed the oil and filter.  Fired it back up to cut some more grass and it started surging.  It was dark so I quit and went to bed.  Woke up this morning and it wouldn't start and run but on full choke!!!  HELP!

Answer
Hello Phil:

If you Used Spray Cleaners to Clean the Carburetor, then the Varnish that was Loosened has come Loose and is Restricting the Carburetor Passages to the Jets. I Always Suggest Soaking Small Engine
Carburetors Overnight to Completely Remove this Varnish.  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.** The Following is an Instruction File I Made for Making this Adjustment. Any Input is Appreciated.  If you Removed/Loosened the Governor Arm to Remove the Carburetor, then Reset the Governor. **To Reset the Governor; Loosen the Governor Arm Bolt and Turn the Governor Shaft Clockwise Until it Stops. Using the Governor Arm Hold the Carburetor to Full Throttle. Now with the Shaft Full Clockwise and the Governor Arm and Carburetor Held at Full Throttle, Tighten the Governor Arm Bolt. If the Engine Still Runs Full Throttle, then Reverse the Rotation of the Governor Shaft, but Still Hold the Carburetor at Full Throttle with the Governor Arm. If it Still Runs at Full Throttle, then Check the Internal Governor.** You can View a Breakdown/IPL of this Engine at this Site Addy, http://www.outdoordistributors.com/ and Select the T. Then Select Tecumseh. Then Select Don't have Part Numbers. Then Enter the Model Numbers. Then Select your Model and Download the File for Online Viewing. Since this is a Tecumseh Engine, I have a PDF Site Addy that May Assist you Also. http://www.tecumsehpower.com/CustomerService/BSI.pdf  . 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