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

If you don't have feeler gauges, a sheet of paper is often about 0.003-0.004" thick. You could try a few sheets of paper to try for a 0.012" gap. You could also temporarily try setting the spark plug gap really small (maybe 0.010") just to see if the spark became more consistent.

>>>Could a coil throw an intermittent spark?   

    Yes.  Can happend with a small open in the primary winding.

>>>Perhaps I should buy a different aftermarket module?

    No.  Without a reading from ground to the spark plug end of the coil other parts won't make any difference.  The coil is defective.  If a new module does then your meter is defective. 

    The coil secondary is a single wire from the sparkplug end, wound many times around the iron core then to ground.  The reading you should get from the sparkplug end to ground is 5800 to 7940 ohms.  You get zero and intermittant spark.  That indicates the coil is defective and has a break in the coil wire.   Since your getting intermittant spark the spark is juming the open sometimes and sometimes it dosen't.  That happens at times and not unusual.  The induced voltage is very high and jumping an open not that difficult. 

    A possibility that give the symptoms is a bad connection from the primary coil to the sprk plug hood.     

If the coil is going to be junked anyhow, could he maybe try cutting off the wire that goes to the plug, near the coil, and replacing it somehow? If it's just 1 layer of insulation (does not also have a shield around it or something), could a small area of insulation be stripped off near the coil, then the wire checked for continuity to the plug while wiggling the wire? That might be a way to see if there's simply a break in the wire?

Hello guys;

I think I will just bite the bullet and contact/order from the guy on ebay who has the coil/module as a set.  I have ordered from him before and he is reliable.  This will be my last shot.  If it does not work, then I will tell my buddy his machine is dead.  I will then take the machine apart, list on ebay, and try to recover my losses.  I'll let you know what happens.  THEN, I will try a little disecting of one of the bad coils!

Broncman,

    Last night I went through some known good SSI coils and got no reading between ground and the end of the secondary.  Very puzzling.  After many hours of poking around it occurred to me that the boot end may not touch the primary wire but be close enough to be jumped by the spark.  That’s the case.

 

    By connecting an alligator clip to the kill tab on the coil (not the iron legs) and the other end to the boot end I could grab both the boot and the primary wire and twist them.  All the coils got a reading and most took a good deal of force to get it.  Five know good SSI coils would not give me a reading without forcing it.  By the way since the first five I pulled out all did the same thing.  It makes me think this is very common.

 

    Your coil may be good and as mentioned in the prior post and just be the boot connection.  It could also be a leak on primary wire to the engine. 

 

    Try the above and if it does not work Ed Stoller suggested this which I’ve never done.  Rip out the primary wire from the coil body.  Clean in there then try to get a reading.  If you don’t then the coil has an open.  If you do there should be a brass nail in the body the coil wire goes onto.  Solder it if you can.  Ed says that’s possible but I don’t see how as I think the insulation would be in the way.  Regardless get a new wire or test your old wire and install. 

 

    If you end up skunked it looks like your plan of ebay would take a while and tie up money.   The expensive coil is in scads of snowblowers and many more lawnmowers.  You could put it aside and wait for a clunker lawnmower to fall your way.  Shops have old mowers and Craigslist guys have piles they post about.

 

   Also, if your coil does get a reading (either of them) you still had intermittent spark.  The symptoms you described can happen with reversed polarity on the Magafire.  I don’t see how but guys have mentioned getting intermittent spark then changing polarity and the engine ran fine.  That’s one possibility.

 

    Another is weak magnets.  Briggs says the magnets should be strong enough to hold and no 10 flat head screwdriver to the magnet.  If your magnets went iffy they could be a problem.

 

    Just say your good coils went bad.  That may have been due to the three magnets.  ??  Before buying another coil you may want to give it a breather and think about all you’ve done before possibly blowing another coil if that’s what happened. 

 

    Which brings up that last point.  Your model and serial number machine does not have an SSI or Xstar per Toro drawings.  What’s the model number of your engine?   

trouts2;

Many excellent suggestions here and I thank you for all you efforts!  I will try as you recommended within the next couple of days.  The engine is model number 47PM1 with a SN of 504804.  Here is a photo of the $%!&$ engine.

   In post 39 I said to disregard earlier post 36.  Post 36 >is accurate< but I found the confusion.  When continuity/resistance testing it makes a difference in reading values if the module is on or off the engine. 

    When on the engine the coil iron will be grounded by it’s mounting bolts.  When on the bench the coil iron does not connect to anything,  Either way, using the iron legs is  not a good place to use as ground.

   Checking continuity and resistance values in non-CDI (SSI) coils is ok.  They are static passive components.  A CDI is transistorized and has an electronic trigger and lots of internal components so getting good resistance readings on a CDI coil only tells part of the coil condition.

   Re-reading what you have said about testing and how it ran intermittently it seems like you could have the wrong ground set on the electronic module or a bad spot on the primary wire or plug hood connection.  The engine is negative ground.  You’ve got to have an excellent ground connection on the module and kill wire.

THREE MAGNETS:

   I found on the net a guy installed a MagaFire II into a 47PM1 and it ran fine.  At first he had the ground wrong and it acted like yours.  Three magnets is no problem.

      On engine identification.  The Toro manuals do not mention the Suzuki 47PM1 for any of the 10 years run of model of Toro 38185.  They show the model as having points but mention 3 other Suzuki engines with CDI ignition but none are the 47PM1.  I checked my records and a few years ago I had a 38185 that had a 47PM1.

Hi trouts2;

I must re-read the posts.  I will try reversing the poles on the mega fire and see how that works when testing for spark.  Regarding the mega fire II mounting, one guy had a photo posted where he installed one.  He hung the module by the hole on the module.  The module itself was not mounted with a screw to any ground source.  Since the mega fire two has two wires coming from it, one of which is for ground, I would not think that the case of the mega fire II itself would have to be bolted to ground. 

Finally though, the plot thickens.  As I stated my flywheel has three magnets.  I tested them by touching them with a 3/8 inch steel rod.  I found one of the magnets to be weak.  The middle one was "very strong". The remaining one was also very weak.  It is almost as if the one in the center is as it should be and the ones on either side are intentionally weak?!?

I tried today to switch the connection on the megafire II module but I still got intermittent spark.  I then took the old coil and pulled out the spark plug wire.  It was very hard to do.  It came out though and I see the little pin inside of the hole on the coil.  I then checked for continuity between the red wire (which connects to the module) and the little pin.  I got good continuity...which I DID NOT get before when I checked between the red wire the and end of the spark plug wire.  Perhaps this is telling me that somewhere along the spark plug wire it was bad.

My plan is to buy a (new) spark plug wire, solder it to the little pin, and then fill the hole with epoxy or liquid electrical tape.  Below is the photo of the coil showing where I cut away a small part of the coil to allow room for soldering.

Broncman,

 

    Looks like you nailed it, great persistence.  Nice picture and neat job.  Hopefully you’ll have a working machine and a spare good coil.  Makes me wish I had the old coils I’ve tossed in the past.  You deserve a victory lap on this one.