Small Engines (Lawn Mowers, etc.): idle problem, blown head gasket, push tube

Question
QUESTION: My John Deere Lx288 vtwin 18 horse.  Will flood when at idle.  I replaced plugs and fuel filter cleaned air filter and put new fuel in it. It runs fine mowing but when you try to half idle it will belch black smoke and flood. Any help?  Thank You very Much  Jeff Price

ANSWER: Hello Jeff:

Send me the Model and Type or Spec Numbers Off the Engine, Please. With these I can Locate the Proper Manual and Better Assist you. The Breakdown Shows 2 Engines Listed for this Mower. One is a Briggs and the Other is a Kawasaki. This Problem can be caused by the Carburetor Needle Valve Not Seating Correctly and Allowing the Carburetor Bowl to Flood when the Engine is Not at Full Throttle. If the Valve Clearances are Not Correct or a Blown Head Gasket Between the Push Tube Galley and the Cylinder can Also Cause this Problem. You can View a Breakdown/IPL of the Engine and Mower at this Site Addy, http://jdpc.deere.com/jdpc/servlet/com.deere.u90490.partscatalog.view.servlets.H and Enter the Model Numbers (LX288) and Click Find. Then Select your Model from the Search Results Area. 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. 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

---------- FOLLOW-UP ----------

QUESTION: Hi John,  I finally got back through to you.  I have a Briggs model 350777 type 1137E1 code 99011911  I am using some mower carb cleaner in the gas tank right now.  It really runs good if you are idled up pretty fast Idled down will start flooding still. I appreciate any follow up.  Sincerely Jeff Price

Answer
Hello Again Jeff:

No Worries. Sometimes the Questioners will Use the Site Addys and Breakdowns and Locate the Problem themselves and Most Times it May be 2 Months before their Schedule Allows them to Do the Diagnostics and Repair Instructions I Sent. From your Description it Sounds like the Carburetor Float Needle Valve is Not Seating Properly (Might be Sticking) and Allowing the Carburetor Flood when at Low RPMs. This is a Common Problem with these Carburetors. 80% of Small Engine Repairs Pertain to the Carburetors and 10% Ign Problems and 10% Engine Problems. I Suggest you Spray some Carburetor Cleaner Into the Inlet Port First. If the Problem Persists then a Good Soaking of the Carburetor is Required.  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), Needle Valve and Needle Valve Seat if Applicable. This is a Flat O-Ring Located in the Inlet Port the Float Needle Rests in. Use a Strong Wire  with a Slight Bend to Remove the Old Seat. Sometimes a Small Pocket Screw Driver can be Use Also. The New Seat will have a Slightly Beveled Side and a Flat Side. The Flat Side goes Towards the Carburetor Body when Inserted into the Inlet Port. Spray the Seat with Spray Lubricant to make Installation Easier. The End of a Drill Bit that is Slightly Small than the Seat can be Use as an Insertion Tool. Wear Gloves or Use a Rag when Handling the Sharpened End of the Drill Bit.  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.** If the Carburetor has Air Mixture Screws, then Let me Know and I can Give you that Instruction File. You can View a Breakdown/IPL of the Engine at this Site Addy; http://www.briggsandstratton.com/maint_repair/manual_and_more/doclist.aspx?categ and Enter the Model Numbers (350777) and Type Numbers (1137) in the Appropriate Boxes and Click GO. Then Select Download 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