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

I turned the key on and have no spark from the plug or even the plug wire when turning over the engine

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

It is a model 38180

Hi fellas;

If anyone is still out here with some ideas, I sure could use your input!

I have become the lawnmower/snowblower repair guy for the guys at work.  I am about 99.9% successful with my repairs but this one has stumped me.  A friend gave me his Toro CCR 2000 snowblower for repair because the local shop wanted 600+ for repairs.  It is the 38185 with serial number 2001010.

No spark here.  I checked and cleaned all connections and re assembled with dielectric tune up grease.  Switch is ok.  I checked the ig modulator with a multi meter and got continuity (which I am assuming is a good thing).  Any way, I purchased a mega star II ignition module and put it in place of the original module.  Still no spark.  (spark plug is good though).  I checked the coil by placing my multi meter from the red wire of the coil to the spark plug terminal.  NO continuity.  I located and bought a used coil from a local shop for $55 .  Yippie...I got spark.  I then put it all back together.  (I had also cleaned the carb and replaced several parts there in).  She started on the first pull!  It ran excellent for 30 seconds and then quit.  No more spark.  I took everything apart again and found the module still had continuity but the coil did not (when I checked from the red wire to the spark plug terminal). 

How could that coil go shot so quickly?  I just hate to junk the machine.  I saw on ebay a coil/modulator combo for about $75.  I dont mind spending that but I also do not know if it is worth the risk.  That may go shot real quick.  What are your thoughts guys?  Thanks very much.

Not sure how much to believe your story about $600 repair cost when you can buy a brand new one (Toro 418) for around $350 with 2 year warranty.

broncman wrote:

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...

Yeah, I am afraid its true about the $600.  They wanted to install a new coil and a new module.  The new coil goes for about $185 plus their markup and I guess the new module for about $150 plus their mark up (close to 400) and probably 2-3 hours labor for another couple hundred.  They charged him $165 for a ariens 5 hp carb rebuild!  Plus my buddy stated it ran better last year than it does now.  Maybe I will just give him an S200 from my collection!

Thanks Niper99...I will double check the ground connection and isolate the switch again.  If I take the switch out of the mix, hopefully I will see a spark.  That would be a wonderful, easy fix!  I will make sure to sand down any paint on the flywheel cover and I will install a new bolt which holds the ground wire against the flywheel cover.  It does seem odd that a working coil would go shot so fast.  The thing that makes me think it is the coil is that when I try to establish continuity with the multi meter (from the red wire on the coil to the spark plug terminal), I get nothing.   Thanks for the suggestions.

broncman wrote:
I've never seen this coil before, so "the red wire" doesn't mean anything to me, sorry. What is the red wire? Is it the wire that leaves the coil, going to the spark plug connector? As in you think there's a break within the wire, between the coil and the plug?

This one is a Rotary 8786 from Tulsaenginewarehouse for 12 bucks. Also known as Nova II.

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. 

Thanks for the input guys.  Later today, I will triple check to get good clean connections and temporarily take the switch out of the mix.  I had bought the Mega Fire II Ignition Module.  The info on this module did not state that it would not work on flywheels with three magnets (this machine has 3 magnets).  My spark plug is good and shows continuity.  I wired the module just like the instructions previously posted showed.  Hopefully my photo has posted.  My coil shows continuity between the (partially red) coil wire and the coil arm.  However there is no continuity between the coil arm and the plug and no continuity between the coil wire and the plug.  I think this means the coil has gone bad.  This week I will have to track down another coil.  Say, the mega fire instructions show one wire being grounded with a screw through the hole on the mega fire and then to the engine.  Must the actual metal case of the mega fire be grounded too, or just the ground wire of the mega fire?  I would not think so since the mega fire has a ground wire coming out of it.  The machine was running excellent (for about 30 seconds).  I will keep the forum posted with updates.

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.

 

    tecumseh_engine_group@yahoogroups.com

Wow trouts2!  Thanks for all that detail.  I know a lot about carb rebuilds, tunes ups etc., but very little about coils.  So that makes a lot of sense that the legs I see are multiple pieces of iron sandwiched together with nothing touching them except where they bolt to the engine.  Setting aside the spark plug wire, there are two wires coming out of the side of the coil.  A small 18-20 gauge yellow wire.  This wire is screwed directly to one of the iron "legs".  The other wire is a 18-20 gauge red wire which connects to the mega fire II ignition module.

I see how the iron core is isolated as you said.  Because of this, as you said, I should get no readings on my basic multi meter when I touch the iron core and any other wire.  This would then include iron core to spark plug terminal and iron core to primary wire (the red wire I keep mentioning) which connects up to the ignition module. 

Would the spark plug wire be connected somehow inside of the winding to this (red) primary wire which goes to the module?  I am not getting a continuity reading when I touch spark plug wire to the primary (red) wire.  This is shown in the lower photo. 

Based upon what you have said, I should NOT get a reading from this primary (red) wire to the iron core.  But I am getting a reading here (as indicated in the top picture).  (short red wire turns into black wire which is the primary wire that connects to the module).  Both the original coil and now (after my 30 second run time) have identical multi-meter readings.

Thank you very much for your time and effort in this diagnosis.