QuestionI have a 19 HP Briggs & Stratton engine Model 42A707.
The engine started to get hot, so I checked all the small things and also did a compression test. All things look normal but I was told that the carburetor was the cause so I used a re-build kit on it. Afterwards, the carburetor looked good. I started the mower, and it worked well until I put it under a load, like cutting long grass, then it lost power and ran rough.
I’m also concerned with something else I was told. With the engine running at idle, I can pull off one spark plug wire to the Left Cylinder and the engine stops. When I pull the wire from the right spark plug, the engine idles rough but doesn’t stop.
Can you also tell me how to check the ignition coil?
Any and all information is greatly appreciated. I thank you for your time in assisting me.
Dan
AnswerHello Dan:
You are Most Welcome for Any Assistance I can Give. After Viewing the Breakdown and From your Description it Sounds like; The Following is a Basic Instruction File I made for this Problem. Any Input is Appreciated. 1- the Coil May be Bad and Not Firing on the Right/Left Cylinder. This is a Common Problem with the Single Coil-Dual Cylinder Coil System. Remove Both Spark Plugs and Wrap a Wire Around the Threaded Area. Attach the Other End of the Wire to the Engine Block. Turn the Engine and Watch for the Plugs to Fire. If Both Plugs are Firing, then 2- Check the Intake Gaskets for Leaks. 3- Check the Both Cylinders Compression. If the Difference in Compression is More than 10 PSI, then you Need to Remove the Cylinder Head and Check the Valve Clearances and Reseat the Valves when you Perform the Valve Clearance Setting Procedure. The Following is a General Instruction File for Setting the Valve Clearance on Non OHV Engines. **Remove the Carburetor and the Crankcase Breather/Vent (# 8-1) and the Valve (Stem) Cover (# 8-2) so you have Access to the Valve Stems, Springs and Keepers. Set 1 Cylinder to TDC on the Compression Stroke. Using a Blade Style Feeler Gauge, Check the Clearances. The Intake should be .004in - .006in and Exhaust .007in - .009in. If the Feeler Gauge will Not Slide Between the Valve Tip and the Tappet, then you Must Reset the Clearances. **You Will Require a Small Engine Valve Spring Compressor to Remove the Springs and Keepers from the Valve Stems.** Some Engines Use a Valve Keeper that is like Automotive Keepers (2 Cone Shaped Keepers that Set in the Valve Retainer/Rotocoil Assembly)and the Other Style is a Slotted Retainer that is Moved (once the Valve Spring is Compressed) to the Larger Opening in the Retainer and the Retainer Slips Over the Valve Stem Tip for the Valve to be Removed. Remove the Heads. Set 1 Cylinder so the Piston is at TDC on the Compression Stroke And Check the Clearances Between the Valve Stem Tip and the Tappet. The Clearances are as Follows: Intake Valve Clearance is .004in - .006in and the Exhaust is .007in - .009in. You have to Lightly Grind the Valve Stem Tip and Place the Valve Back Into the Engine (you can Hold the Valve Seated by Hand) and Check the Clearance Until you Reach the Required Clearances. Once the Valve Clearances are Reached, Re-Install the Valves on that Cylinder and Turn the Other Cylinder to TDC on the Compression Stroke and Set that Cylinders Valve Clearances. Once that Cylinder is Set, then Re-Assemble the Engine.** 4- If One Cylinder is Not Firing or is Firing Intermittently, then Replace the Coil. 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) Numbers Example: XXXXXX and Click Search. Then Double Click on the Model in the Results Area. Select Sectional Index. Now you can Select the Section of the Engine you Wish to View. 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
