Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) Discussions

How do I know if it is the coil magneto or the xstar module magneto?

It is a model 38180

l would first Double check the small wire that goes to ground from coil and make sure u have a GOOD and CLEAN bare metal connection there....also lve have replaced alot of those kill switchs so that may be your issuse... clean the ground connection and disconnect the kill switch then see if u got spark...if not u got a bad coil....l dont recall having to replace a coil on that motor before... and the odds of another coil going bad seems unlikely but it happens...

Niper99, check me on this,

   The module has two tangs.   Regardless of color one tang is positive, the other tang negative.  Depending on your grounding one lead goes to the coil wire (the one cut away from the ponts) and the other to ground.     Done.

   If  a stop switch is included how it gets wired could vary slightly. 

   The non-grounded wire from the tang could go to the switch then to the coil.  So the switch would create an open or connection.

   The non-grounded wire from the tang could connect with a wire nut.  From there one wire run to the coil and one to one side of the stop switch.  The other side of the stop swith would go to ground.

     Again depending on your ground being plus or minus one tang is grounded and the other wired as above.  Not for use with battery start engines or flywheels with multiple magnets. 

Below shows the armature or iron core.  The coil is electriclly isolated from the core.  Yhe test leads as shown should read zero ohms.

Below 24 is the armature or core.  No connection to anything.  48 is the trigger coil for the transistor controlling the low tension side of the coil at 36.  The magnet loads it's flux into the iron core (24) and induces a current on the output side of the coil (86)  The armature core is usually mounted to the engine by a bolt so grounded.  If you get no reading between the armature and the sparkplug end that's good.  You got a reading to the other wire.  Where does that go? 

   The Mega fire case tab should be grounded.  Most directions show the ground wire going on top of the tab and both screwed into the engine, grounding both.  The tab gets grounded and the wire on top gets its ground from the tab.  You’d have to have a physical and electrical schematic to be sure but that’s the way a few makers show them connected.

   Megafire and Megafire II directions are different over time but both say both won’t work with multiple magnets or nothing about magnets.  Multiple magnets do not make sence with the design.

   BUT people have success with multiple magnets…...  Depending on when the magnets cross the coil in the timing cycle people get lucky and it will fire properly and either not fire on the following magnets as it’s not ready or be firing into an unloaded combustion chamber to no effect.

Testing:

     Generally speaking you could look at the black coil module in the picture you posted as a whole and the two things sticking down could be called arms or legs.  The could be called the arms or legs of the coil when talking about the whole lump of the black thing, the solid state ignition. 

   BUT… The coil arm you mentioned is really the arm or leg of the iron core and not specifically the coil in the electrical sense.  It’s isolated from the coil windings, does not touch the coil windings and does not pass current to them directly by contact.  The flux generated by the magnet, gathered and directed by the iron core induces a current in the coil through the air, no touching.   You won’t get a continuity reading from the iron core to any wire unless it goes to ground as the iron core is bolted to the engine.

   For regular coils when they talk about resistance testing from the “leg” of the primary to the other side they are talking about going from coil lead wires not the core.  The same for resistance checks on the high tension side.  The  

    You got no reading from the core to the spark plug.  I think that’s ok.  I’m not sure about the other wire.  Where did that wire connect?  Unless it connects to ground there should not be continuity to thr iron core arm/leg.

    Once you get the molule mounted you can test by just spinning thr flywheel by hand for spark.

   A guy who’s really good at SSI’s is Ed Stoller his website is at  http://home.earthlink.net/~edstoller/

   He’s available at the Tecumseh reflector or used to be. He’s a great guy and about the most savvy guy on the net on SSI’s.  If you email to the adder below and he’s around he’d be a big help.