My Snapper RE110 has a new battery, coil and spark plug. The engine will turn with the starter engaged but I am not getting any spark at the plug. Is there a safety switch that I need to check? This mower was given to me without any history. The brake and seat safety switches seem to be good since the starter works when the key is turned.
In the steering wheel column housing I fount these wires unplugged. Where do they need to plug into? Also above the key the appears to be a momentary toggle switch that has nothing connected to it.
Any help is appreciated.
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#2
mack1611
Those wires in the column are for the addition of a headlight.
#3
mattm55
"The brake and seat safety switches seem to be good since the starter works when the key is turned."
You'll have to diagnose the electrical issue with a meter over the "seems to be good" method. Isolate all the switches or test continuity to "verify" ALL the switches work as designed.
I would
1. remove the dependencies on the switches temporarily (carefully). You can even remove engine cover, spark plug and put plug in boot and hand spin motor to see if sparking with all electrical wiring removed causing a grounding of coil.
2. check proper air gap on coil?
Pull the kill wire off the coil. Should drain the tank dry if the coil is good.
Remove the coil. Sand/polish the coil mounting pads on the coil and the engine block where the coil sits. Clean all the rust off the coil mounting areas. This will restore the coil ground.
No need to sand the flywheel magnets.
Make sure the clutch/brake is pushed all the way down when starting.
Do you have a pull rope or just electric start? If a rope, pull the spark plug out and test for fire.
It is a magneto with a Hall effect trigger chip in embedded in the coil
So you check is with an oscilloscope and a frequency signal generator and preferably a variable flux pulse generator not a Ω meter like you check a car coil.
That little package will set you back from $ 30,000 for cheap production stuff to $ 500,000 for research grade equipment .
And if the coil fails it is not repairable other than to replace the HT lead & plug cap so it is a moot point which is why we simply disconnect the kill wire to determine if the problem is internal or external .
Unfortunately you tube & face book is full of morons there to appease their egos posting total BS and those who do not know any better see their "Hero" supposedly working miracles with a $ 10 Walmart tool so they repost it .
This process continues till 50,000,000 posts are up there by which time fiction becomes fact and those that actually do know the facts & truth are demonised .
#7
mack1611
So when I can read Resistance on a good mag and get no reading on a bad mag that's just fiction?
Can you resolve a Hall Effect trigger ?
And do you know if the trigger is set to NO or NC
Or if it works on the + side of the induced voltage or the - side of the voltage
Or to put it another way
Using an Ω meter to test a modern coil is the same as using a multi meter to test a coil by measuring between the points fixed terminal & the coil
BEcause we can see a set of points then we know if they are open or closed
Well the magneto has an electronic set of points ( called a Hall Effect Trigger ) between the kill wire & the output wire
Now this is solid state electronics so you can not tell is it is open , closed or closes / opens when the multimeter sends the signal down the kill wire
And just so you fully understand your multimeter measures resistance by sending a very low voltage through the probes and measuring the voltage drop.
That is how they work
So if the voltage is above the trigger voltage ( or below if it is a - trigger voltage ) then the meter itself can cause the trigger to trip
Further more if you have a cheap meter that sends a relative high voltage signal down the probes and you have the polarity round the wrong way that signal can fry the Hall Effect chip
I have actually been in that situation where a customer came back with his new coil claiming it was faulty
I installed it in my test rig ( flywheel mounted on a lathe ) and sure enough no sparks
So I replaced it with another then made a warranty claim against my wholesaler
A week latter he was back with the same problem and yes no sparks again
Thinking I had a bad batch of coils I got another one out of stock but this time I tested it before I gave it to the cuatomer so I know it was good before he cam to pick it up .
And you guessed it, he was back next weekend and got very agressive when I told him I tested it before I gave it to him & it was working perfectly so there was a problem with his mower
He got really abusive then exploding that I was f-Wit moron thieving bastard because he had not even fitted it to his mower
So I asked him how he know it was dead
The reply was he tested it with his multimeter as he had seen done on You Tube
I then asked on what setting with what tool & how he connected it
And yes the clot shoves the + lead on the - kill wire with his meter set on MegΩ
So I threw him out
Being a total A-hole he made a consumer complaint against me & I was ordered to refund his money which I refused to do so it became a court matter .
The man who invented the Hall Effect chip was a customer of mine in a previous business & I got him to come and testify as an expert witness
End result
Prosecution denied , he was ordered to compensate me for the good magneto ( $ 65) he destroyed + $ 250 in witness expenses for both me & my witness + $ $450 in court costs + his legal fees
#9
mack1611
I guess I got lucky when I replaced my coil and my mower ran again.
It is not luck.
It is understanding that on specific subject forums where no one is making money you will get sound information from people who actually either know the theory or practically have done it many times before or even both
On platforms that either massage the egos of idiots or provide means of monetising content you are most likely to get trash .
having said that some coils that are normally closed can have their coils tested with a multimeter and in fact some Kohler & Kawasaki manuals do have resistance readings
However that that just tells you the windings have continuity at room temperature
None of them provide information on what transistors & resistors are used so you can not test the triggering function
Now to complicate things most Hall Effect triggers have a retarding mechanism built into them to make starting easier so they have multiple circuits and some coils even have multiple contacts on the primary windings so they can vary the spark timing & intensity.
When Atom Industries first marketed their "computerised Ignitions" ( well it was the 60's ) they came with different retards ( which we call advance for some silly reason ) enclosed in different coloured cases
We used to use the purple ones for our racing Bantams as they would run up to 13,000 rpm ( which you do not want to do on a Bantam for very long ) .
The downside was variations in the strength of the flywheel magnets and variations in the air gap caused variations in the spark timing.
To over come this some engine makers took the simple induced current control circuits and converted them to a fixed voltage supply system running off battery voltage, thus the SAM system was born and when they worked they worked exceedingly well producing substantially more torque than either points or a standard Hall Trigger .
However when they did not work, they did not work big time, they were both expensive to make & difficult to fault find so eventually got dropped
And of course once the Hall circuits got embedded into the magneto coil which then became a "module " at 3 times the combined price of a stand alone trigger & standard coil , testing became a moot point as they are not repairable so it is a case of works or gets replaced
Oh an Atom are still around
They currently make edge trimmers , petrol powered augers & drills but not their modules any more as once patient had expired every one who did not use them under license reverse engineered their own modules, thus the B & S "magnetron"
Thank you for your explanation. It's very helpful. I could get out my scope and signal generator is I wanted to play with a $50 part. Now this makes sense why the simple continuity test shows a shorted coil sometimes and not others. Now it sounds like I have a fuel problem since I get a spark and it cranks and dies if I put a little gas in the carb.
