Small Engines (Lawn Mowers, etc.): engine cut out, john deere lt 155, jumper wire

Question
John Deere LT 155 (Kohler engine) tractor lawnmower cut out when warm. Can jou help with problem?

Answer
Hello Barend:

>>This Problem can be Caused by 1 of the Following. I Give the Most Common Cause First and So on. You May Want to Perform the Checks in a Different Order. 1- The Ign Coil is Heating up. Check the Coil, Remove the Blower Housing (metal Engine Cover) and Disconnect the Cut Off Wire from the Coil. Remove the Spark Plug/s and Wrap a Wire Around the Threaded Area of the Plug/s. Attach the Other End of the Wire to the Engine Block. Turn the Engine Over and Watch for Fire at the Plug/s. If you have Fire, then a Safety Switch is Bad of there is a Ground in the Wiring Harness. If No Fire at the Plugs, then the Ign Coil is Bad and Requires Replacing. If your Engine has Bot a Coil and an Igniter, then Remove the Coil and Igniter and have them Checked at a JD Dealer or a Small Service Center that has the Required Test Equipment. 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 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. To Check the Safety Switches; The Following is an Instruction File for the Safety Switch System. Any Input is Appreciated. The Color Code of the Wires May be Different than those I Use as a Reference in the Instruction File. **PLEASE REMEMBER THAT THE INSTRUCTIONS FOR CHECKING THE SAFETY SWITCHES IS JUST THAT!!! FOR CHECKING ONLY. I NEVER Suggest a Mower be Operated with a Safety Device or Switch Disconnected or Bypassed. Now. On Some Model Mowers you can Simply Unplug the Safety Switch from the Harness. On Other Models you have to Place a Jumper Wire Between the Harness Terminals (on the 4 Post Switch (Clutch/Brake) Jumper from Same Color Wire white to White First and then Check for Fire, Now Include the Black to Black Wires if No Fire. Check the Clutch/Brake and the Blade/PTO Safety Switches First. Check the Seat Safety Last. Usually the Seat Safety is Not in the System for Starting the Engine. Just to Ensure Someone is in the Seat when Engaging the Transaxle and/or Blades. Use a Paper Clip or a Short Wire to Make a Jumper.**  2- The Carburetor Solenoid is Heating Up and Restricting the Gas Flow to the Jet. The Engine then Requires 3 to 4 Intake Strokes to even Attempt to Start and Usually you Get the Backfire through the Carburetor Due to Hot Gasses Inside the Cylinder Igniting as the Next Air and Gas Mixture are Entering the Cylinder. The Gasses Ignite while the Intake Valve is Open. The Following is a Basic Instruction File I made for Checking the Carburetor Solenoid. 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.**  3- A Sheared Flywheel Key. Over Time the Flywheel Nut May Loosen Due to Vibration and Heat Expansion and Contraction. When this Happens, the Flywheel Usually Damages the Key when the Engine is Shut Off. The Sudden Stop will Move the Flywheel enough to Cause the Damage. This Damage Causes the Coil to Fire the Plug to Early and the Backfire Occurs. A Steering Wheel Puller can Usually be Used to Apply Enough Pressure to Remove the Flywheel. The Following is the Instruction File I Made for Removing the Flywheel from Most Mower Engines.  It is the Basics and if you have a Question, Please Ask. Any Input to Make this File Better is Appreciated. ***Disconnect the Coil Wire from the Spark Plug. Remove the Blower Housing (metal engine cover). Remove the Coil. Remove the Flywheel Nut or Starter Cup (Depends on the Model). Now Attach a Steering Wheel Puller to the Flywheel Using the Threaded Holes in the Flywheel. Tighten the Puller. Now Hit the Puller with a Hammer. Repeat this Procedure Until the Flywheel Pops Up or can be Lifted Off the Crankshaft. On Some Models you Can Not Use a Puller and Must Use a Pry Bar and a Pipe Cap that is Slightly Larger than the Crankshaft. Place the Pipe Cap Over the Crankshaft to Protect it. Place the Pry Bar Under the Thick Section of the Flywheel and Pull Up Against the Flywheel. **BE CAREFUL  DO NOT PUT A HOLE IN THE BLOCK UNDER THE FLYWHEEL** Now Hit the Pipe Cap that is on the Crankshaft While Applying Pressure Against the Flywheel (covered with the Pipe Cap). Repeat the Procedure Until the Flywheel can be Lifted Off the Crankshaft. *** Be Sure you have the Flywheel Torqued to the Proper Torque (I require the Model and Spec/Type Numbers Off the Engine to Provide the Proper Torque) and Set the Coil Gap to .020in.. 4- Make Sure the Gas Tank cap is Venting the Gas Tank. If this Unit has a Tank Screen, then Remove the Tank and Place a Few "Steel" BB's in the Tank. Replace the Cap and the Shake Vigorously in All Directions for a Few Minutes. Remove the BB's with a Mechanics Magnet and then Blow Out the Tank with Compressed Air. Remove the Tank Outlet Port and Clean the Port. If the Outlet is a Fixed Port, then Blow Out the Inlet Back in to the Tank and then Blow out the Tank. Make Sure the Tank is as Clean as Possible. Use a Lint Free Rag and Use a Long Screwdriver and Wipe Out the Insides of the Tank for a Final Clean. If None of the Above Corrected the Problem, then there is Internal Damage to the Engine.
>>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. Be Safe and Happy. Thanks.

Good Luck

Respectfully

John

PS: I am Allowed to Answer 5 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. Comments and Ratings are Greatly Appreciated. Thanks.

Respectfully

John