Briggs and Stratton 3-6HP Ignition Coil Service

Here we will demonstrate how to check, service or replace an ignition coil in a Briggs & Stratton 3.5HP

this is similar in most Briggs & Stratton engines between 3-6HP

Tools/Parts Required 

  • Phillips Head Screwdriver
  • Socket Wrench - 10mm & 8mm Sockets
  • Wire Brush Optional

Step 1.

Remove throttle cable and top cover from the lawn mower. Ensure that the spark plug and the spark plug leads are not in contact.

Step 2

Inspect the position of the ignition coil to ensure it is in close enough proximity to the fly wheel. Then remove the ignition coil by loosening screws attaching it (also disconnect the wire attached to the ignition coil).

Step 3

Inspect the wire previously connected to ignition coil for any damage.

Step 4

If needed use the wire brush attachment and the electric drill to remove any rust present on the metal portion of the ignition coil, closest to the fly wheel when screwed into position (be careful not to separate the layers of metal forming this part of the ignition coil). Also remove any rust present on the magnetic strips located on the fly wheel.

Step 5 

Re-install the ignition coil, remembering to first re-connect the wire previously attached, then test the spark of the mower. If there is still no spark occurring it is likely that the ignition coil needs replacing.

Step 6

Assuming a spark is now being generated, place the cover back over the engine.


  1. 1. The rust on the flywheel magnets or the armature does not effect the spark.
    2. The small little flaps of metal are called laminations.
    3. The primary and secondary windings on the coil should be checked for continuity with an ohm meter.

  2. How much should the resistance be my meter on both ends read 9.75 k ohm on on old 500 series 158 cc Briggs and Stratton lawnmower.

    • Hi Antonie

      We do not know the reading for all coils, Some of the earlier briggs coils are okay between 2.5-5K ohm others are not, The only sure way to know is to compare to a new coils reading

  3. I have an old Rover edger runner 4 cycle engine 2hp wires from the coil goes inside of the engine,how to replace the coil have no spark, do i need to replace the coil with what type of coil.

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