Small Engines (Lawn Mowers, etc.): testing a coil on a B&S, spark plug wire, hp engines

Question
Hi Eric, hi gang.......I have a 3 1/2 hp B&S engine that has NO points under the flywheel. I don't have any spark, and after checking the Snapper and B&S sites, I've determined that I have a "Magnetron" coil. I have 600 ohms resistance from the base of the coil, (coil off the mower) to the ground/spark plug wire, and I have 175 ohms resistance from the lead (the little wire that goes to the ground cut-off switch). How can I tell if the coil is good or not, since I can't find the values?

Thx!
Lee


Answer
Dis-connect the small wire on the coil.  Some early Manatrons soldered the wire to the module.  If you have an early model, you can dis-connect the wire at the throttle shut-off switch...just follow the wire.

With the shut-off wire dis-connected and the coil mounted/gapped check for spark.  If you do not have spark with the small/ground wire dis-connected from the coil, remove the coil and clean the mounting posts and coil.  Re-install and check for spark.  If you still have no spark then the coil is bad...99.99999% of the time.

You can purchase used coils from a lot of dealers.   Those coils have been used for years and fit a wide range of 2-5 HP engines.  No warranty on a used coil but could save you some cash.  

Eric