Small Engines (Lawn Mowers, etc.)/No start, Briggs & Stratton


Have a three year old Briggs on a Poulan push mower.
Mower Model PR550N22SH, engine model 1000000 Q 500/550 series.
Cannot get a spark.  Has compression, has fuel delivery, the plug gets wet, not oily.  No spark with the plug or with a  spark plug tester.  No points, only has three ignition parts; the coil assy, the flywheel and the cut-out wire.  Disconected the cut-out wire, not a problem, no spark on or off.  Replaced the coil assy, gap at .10 inch, no spark, three magnets on flywheel, center one strong, leading and trailing magnets seem okay but weak. bars embedded in opposite side of flywheel are non-magnetic. How does this electronic ignition work?  What could it be?  Only thing to replace is flywheel or entire engine.  How can one get a spark out of this #$%#$% thing?  Is there a special way to test the coil?  It has 5000 ohms resistance and continuity, same as new one. I've been searching for a service guide on this for days.  Would appreciate any help you can give.

Leave the shut-off wire dis-connected to verify/test spark.

Get a new spark plug!  Test for spark?  No spark?  Is the coil on upside down?

Never saw magnets go bad...has to be the coil.

When the magnets rotate past the coil the create a magnetic field across the coil primary winding.  When the magnet pole passes and switches direction the primary field collapses and generates voltage in the secondary which produces spark.  All of this is aided via some basic gizmos (transistors) inside the module.

Dis-connecting the cut-off wire and checking for spark is the best way to check the module.


Small Engines (Lawn Mowers, etc.)

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Eric A. Jones


Lawnmower Repair . Certified Master Service Technician from B&S. Have 23 years experience on B&S, Lawn Chief, Weed Eater, Echo, Peerless, Wheel Horse, Snapper, Atlas, MTD, McCulloch, Homelite and many other numerous brands. Specialize in electrical repair.


Born and raised in the midwest. Started tinkering with engines when I was about 14 on my Suzuki RM-80. I began lawn mower repair at a small hardware store. I knew absolutely nothing. I read lots of repair manuals and met an older fellow who taught me many lessons. I continued working on small engines through high school and paid my way through college working on mowers at the same hardware store. Decided to get away from the midwest and mower repair so I joined the Air Force. I repaired air traffic control electronic equipment and ended up in Hawaii where I got a part time job at Small Engine Clinic. I gained a lot of experience from the Small Engine Clinic and had a blast repairing small engines. I then took the Briggs and Stratton Master Service Technician test and earned my MST. I then traveled to Wisconsin where I attended the factory update training seminar and received formal training. Continued working on mowers part time as I completed 20 years of military. Retired from the military on a Friday and continued in the lawn and garden industry the next Monday.

MAS Aerospace Operations BA Mathematics AAS Electronic Communications AAS Electronic Technology

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