Magneto Contact gap

  1. Unbolt magneto and remove its distributor cap and contact cover plate.
  2. Remove magneto to a bench make sure the vernier coupling is marked and not lost
  3. Check the gap with a feeler guage and adjust with magneto spanners if necessary.
  4. Reassemble

Note. It is possible the magneto is 360 degrees out at the crank, so attempt changing the alignment if the appliance will not run subsequently.


  1. Plug in a strobe lamp, and connect it to No.1 Spark plug.
  2. Shine at the flywheel on the offside of the engine.

It should be:

  • 40-50 deg fully advanced
  • 10-20 deg fully retarded

Spark plugs

Check clearance and clean off any deposits

Set magneto plugs to 25thou

Do not adjust the 7-com-l plugs unless they are causing problems with starting.