Small Engines (Lawn Mowers, etc.): coil question, resistance measurements, coil tester

Question
Hi Eric.  I have a Tecumseh HS40-55513e on a snowblower.  It has no spark.  I changed the plug, isolated the ignition from the cutoff switch, then went after the old points and condenser, replacing them with a Stens electronic ignition.  Nada.  When I measured the resistance on the coil, I read a short on all three leads--spark plug, the lead to the electronic ignition, and the ground lead.  All three leads read open circuit to ground.  Assuming I haven't botched my wiring (I've converted a few engines to electronic ignition), my next step is to replace the coil.  My question is that I've never had a coil go bad and I don't know what resistance readings are supposed to be.  I'm guessing that I should be reading an open circuit on at least one of the three leads coming off the coil, but its just a guess.  What exactly are the three leads and what should I be reading between them?  Thanks.

Brett

Answer
There is no exact resistance reading published my most American engines.  I have had some specs on Japanese engines but had one coil that checked good (resistance) but still would not work.

I Googled "small engine coil resistance" and found all kinds of links with various specs.  Here is one link:

http://www.mytractorforum.com/showthread.php?t=88762

I would not trust resistance measurements.  If the coil is shorted or open then it is bad.  

Test the coil, without the electronic ignition kit, and see if it is open or shorted.  If there is no open or short check the kit or try another kit.

Have you called you local mower shop to see if they have a used coil or can test the one you have?  We have a coil tester that simulates the flywheel magnets and measures the resistance as well as high voltage output.  However, coils can stop working when they get warm via the engine operating.

Eric