Small Engines (Lawn Mowers, etc.): Small gas powered lawn mower, spark plug gap, briggs stratton

Question
Dear Mr. Bridgers
Thank you for your prompt response (I read it on 2/16/08). First, my previous question was very poor, and I'll clarify now:
I have a Murray Mfg Co 21" 3.5,model #21661xBB with Briggs Stratton motor-engine lawn mower, which I could not start it. I followed your advice to others in this web site, and cleaned up gas tank and filter and sprayed carburetor fluid to carburetor external. Put new gas and oil but mower did not start. My friend told me to replace spark plug (Champion RJ19LM). I did and mower tried but it did not start. I then used startup fluid and mower started quickly. I ran it for 15 minutes and I stopped it. I tried to start it again but it failed (it just made a few turns and stopped). Again, I applied start up fluid, bingo started and ran very well. The seller at auto zone did not know anything about spark plug gap, which makes two of us. What do you think about this problem? By the way I don't have mower manual, and don't know anything how to remove the carburetor for a thorough clean up
Thank you very much for your valuable time and patience.
Joseph

Answer
Hello Joseph:

The Plug is Gapped to .030in - .035in. The Carburetor Choke Passage in the Carburetor is Restricted and the Carburetor Require Cleaning to Operate Properly. Here are the Basic Instructions for Removal of the Carburetor. For the Running Problem. **Usually a Breakdown of the Engine and Carburetor is All you Require to have as a Reference to Remove and Clean the Carburetor. If you DO Hit a Snag or Just Require More Detailed Instructions, Do Not Hesitate to Ask, Please.  **REMEMBER You Do Not have to Remove the Welch Plugs. The Following is the Instructions for Proper Carburetor 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 this Engine at this Site Addy, http://www.smallenginepartswarehouse.com/parts.asp and Select the Shop Online Parts Look Up. Then Select the Model Tab. Then Select the OEM and Enter the Model (5 or 6 Digits) and Type Numbers (first 4 digits Only). Example: XXXXXX-XXXX. Then Double Click on the Model in the Results Area. Now you can Select the Section of the Engine you Wish to View. Go to this Site Addy, http://www.smallenginepartswarehouse.com/parts.asp and Select Shop Online Parts Look Up. Then Select the Model Tab. Then Select the OEM (Murray) and Enter the Model Numbers. Then Double Click on your Model in the Results Area. Then Select the Section of the Unit you Wish to View. Hope this Helps. I am Here if You Require More Assistance. Let me Know What Happens, Please. 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 9pm EST (US). My New Day Starts then. Thanks.

Respectfully

John