QuestionHi, I'm hoping you can help me with my problem. I have a Craftsman (AYP) riding mower with a Briggs & Stratton twin cylinder 19.5 hp engine (model 42E707, type 2631 E3). It has electronic ignition. The last time I used it in the fall, the mower stalled after running out of fuel. I added some fuel but it would not restart. I decided to add some fuel stabilizer, then cranked it a few times and stored it for the winter. I took it out this spring and changed the fuel filter, air filter and spark plugs. It still would not start. Fuel was being delivered, but there was no spark. So I purchased a new coil. It started fine. Then after 10-15 minutes, the engine started sputtering and it backfired, then stalled and would not restart. Again, no spark. Exchanged the coil for a new one, and I had the same exact experience. This time, I checked the flywheel key by removing the nut which fastens the flywheel. The flywheel key appears to be in the groove in the correct location - i.e., it does not appear that the flywheel is out of position. I did not physically remove the flywheel as I did not have a puller, but I could see the key. I'm unsure what to do next at the risk of continuing to throw money at it. If I rebuild the carburetor, will I be able to tell by its condition if it is likely causing the issue? My fear is that I rebuild the carb and it does not correct the problem, and I wind up wasting another $50 on a coil. Thank you very much for your advice.
AnswerHello Victor:
Even if the Flywheel Key is Damaged, the Spark Plug will Still Fire if the Coil/Magneto is Good. Anytime the Magnets on the Flywheel Swing Past the Coil/Magneto, No Matter if the Flywheel Key is Damaged or Not, it will Fire the Plug as Long as the Coil/Magneto is Not Grounded. The Shut Off Wire Grounds the Coil/Magneto to Stop the Plug from Firing. The Following is an Instruction File for Checking the Coil/Magneto. **To Check the Ign Coil; Remove the Spark Plug/s. Wrap a Wire Around the Threads of the Plug and Attach the Other End of the Wire to the Engine Block. Remove the Blower Housing (metal engine cover). The Wire that is Connected to the Coil/Ign Module from the Shut Off Switch needs to be Removed (unplugged) from the Coil/Ign Module. Now Check for Spark at the Plug. If Spark, then the Shut Off Switch or the Wire is Bad. If Still No Spark, then the Coil/Ign Module is Bad. If there are Safety Switches on this Unit and the Coil is Good; you Need to Check the Safety Switches for Being Bad Also.** FYI; I have had many New Coils Function for 10 to 30 Minutes and then Cause the Same Problem you Described. ***Remember, if the Coil/Magneto Test Shows the Coil/Magneto is Not Firing with the Shut Off Wire Disconnected, then the Coil/Magneto is Bad.*** 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 (42E707) and Type Numbers (2631) 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
Hi Again Victor:
I Just Read your Post and Felt I needed to Respond. Thanks for the Ratings. The Carburetor will Not Cause the Coil Not to Fire the Plug. If the Coil is Not Firing, then it has to be the Coil. It takes 10 to 15 Minutes for a Coil/Magneto/Solid State Ign Module to Reach True Operating Temperatures. Other than the Coil for No Fire to the Plug, is a Bad Shut Off Wire and you Stated you were Operating the Mower with this Disconnected. The Other Cause for an Engine to Quit after 10 to 15 Minutes of Running (but the Plug still has Fire) are; 1- the Gas Tank Cap is Not Venting the Tank and, 2- Trash Accumilating at the Tank Pick Up and Restricting the Gas Flow to the Carburetor. Till Next Time. May All Your Mechanical Problems be SMALL ONES and May the All Mighty Bless You and Yours. Thanks Again.
Best Wishes and Good Luck
Respectfully
John
