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Hey Guys,

I have a Briggs 126T02-0675-B2 that isn't getting spark. I ohmmed out the coil, determined it to be bad, replaced it, as well as the spark plug. Still no spark. I ohmmed out new coil, seems good, I ohmmed the kill wire and seems to function as it should with the lever. I checked the magnets on flywheel, seem to be grabbing. I guess only concern is, it appears to have mags 180 degrees off, but there is NO magnetism there...not sure if only one set of mags or 2 is normal. I tried the airgap everywhere from .06-.12...I started at 12 as I googled it quick figuring it's pretty universal, later found a chart that says this motor to be .06-.10 so I fiddled with it all the way up, 6, 7, 8, 9, 10. I can't for the life of me see anything else in the line to prevent spark, everything seems to be normal, but still nothing. What am I missing??

Thank You in Advance,

Eric

I’m not being a smartA, but could you have installed the coil upside down? It has been done more than once.

Well, it says cyl side and this side out. I tried spinning flywheel both directions too, so even if it was upside down, wouldn't reverse rotation cause spark?

I think I may have found the possible issue...the kill terminal on coil itself, even when completely removed from mower, shows short to ground...but the kill wire when isolated is grounded until the handle is held down...so this tells me that to start up, according to the mower, the coil kill must be ungrounded...if this coil kill is grounded ALL the time, the spark is going right to ground, not chaRging the secondarys...do I have a bad or incorrect coil?

You’ve found the problem.

You may have a bare spot on the kill wire, just it disconnected and try starting. Just be prepared to either plug wire, choke the engine to death, or clamp the fuel line to shut the fuel to the engine.

StarTech said:

You may have a bare spot on the kill wire, just it disconnected and try starting. Just be prepared to either plug wire, choke the engine to death, or clamp the fuel line to shut the fuel to the engine.

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No spark even when unplugging kill wire

I just noticed in the parts diagram it says to order a new air vane when replacing the coil...doesn't make much sense to me, can someone shed some light on that?

I am curious how you are determining there is no spark? I had a crappy spark detector that I used for 2 years. I had a machine that I could not get spark on. After messing with it for days I realized the spark detector was broke

waylonJ said:

I am curious how you are determining there is no spark? I had a crappy spark detector that I used for 2 years. I had a machine that I could not get spark on. After messing with it for days I realized the spark detector was broke

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grounding plug to head bolt

HemiMoparGuy1981 said:

I just noticed in the parts diagram it says to order a new air vane when replacing the coil...doesn't make much sense to me, can someone shed some light on that?

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I mean, I get that it can cause a no start issue by wrong position of choke, but, I don't see how it'd cause a no spark issue and why you have to replace both the coil and the air vane

That is because coil physical shaped changed. I got engines where there are mods to the engine's shroud and cylinders in order to fit the new coil's.

Now if the magnets are strong and there is still no spark with the kill wire then the new is probably bad too. It is not unheard of receiving a bad new coil.

I have purchased new coils before and sent mowers out the door then 2days later they return with same problem no start issue remove new coil ohm it out and find its actually above where its supposed to and this is an OEM call they send me replacement before installing I ohm that one and do what same thing so here we go again with some more calls and tech people finally end with an aftermarket that ohm's at 2.75 and not over 6 ohms so I now ohm them all when new.

Maybe I can learn something new today. I was under the assumption that today’s coils with Hall effect sensors in the primary circuit can’t be accurately tested with an OHM meter due to internal circuitry. Second question, where are you getting the specs on This coils?

Briggs ohm specs are in there manuals your only measuring resistance between secondary and ground and primary and secondary or ground just like checking a motorcycle coil only they work differently but resistance is resistance if the field is broke or then resistance can be low if a capacitor inside is bad then resistance can be high todays coils work much better then yester yrs did as for timing advance when needed now Kohler coils are a different breed and not so simple.

Ok, I'm at a loss. 3 coils, 2 brand new all ohm out with the kill terminal grounded internally, starting to wonder if it is normal

It just doesn't make any sense though...releasing the handle creates a connection to ground for the kill wire....so logically, grounding the kill terminal removes power from the coil. If the kill terminal is grounded internally to the coil frame, then the frame of the coil is bolted to the motor, it is making that connection to ground permanently, which logically says the coil will never be able to be powered.

HemiMoparGuy1981 said:

It just doesn't make any sense though...releasing the handle creates a connection to ground for the kill wire....so logically, grounding the kill terminal removes power from the coil. If the kill terminal is grounded internally to the coil frame, then the frame of the coil is bolted to the motor, it is making that connection to ground permanently, which logically says the coil will never be able to be powered.

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The coil is not "powered" like a car coil it is self generating like an alternator coil
When the small wire is grounded the coil produces no spark & the engine stops
When the wire is open circuit power is accumulated in the coil which goes to ground through the spark plug
To simplify things.
So to run that wire must be open circuit to ground
To stop it must be closed circuit to ground.

You might check to see if there's any voltage going through the kill wire to the coil. From what I understand, that'll blow a coil.

bertsmobile1 said:

The coil is not "powered" like a car coil it is self generating like an alternator coil
When the small wire is grounded the coil produces no spark & the engine stops
When the wire is open circuit power is accumulated in the coil which goes to ground through the spark plug
To simplify things.
So to run that wire must be open circuit to ground
To stop it must be closed circuit to ground.

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Right, I get that...it is powered by the magnetism...But with the primary coil internally grounded, the spark powered by the magnets goes right to ground instead of charging the secondary and creating a spark. But I have 3 coils that are internally grounded at the kill wire, and no spark with the correct spacing with feeler gauge, plenty strong magnets, kill wire ohmming out, switch acting as it should (open when handle is down, grounded when released) There isn't much to this stupid circuit, but it still isn't working.

There is no way to bench test small engine coils without special big bucks equipment. The only test you can Do is test the secondary resistance with should be 2500-5000 ohms if good. There is no test for the primary circuit, so if you are trying to test this, you are just wasting your time. Brian, your primary ohms specs are for coils used in points engines. I used to have a schematic of a coil with a Hall effect sensor, (which I can’t find) but if I remember right there are there are three different circuits, one of which is grounded, but it is not the kill circuit. I think you are overthinking this and assuming it works a certain way. Anyone who has had to troubleshoot electrical problems knows that assuming only gets you in trouble. Having one bad new coil happens, two bad maybe, three bad something is not being done right. At this point I suggest that you take a coil off a running engine and install it on your unit. If it doesn’t fire, something in your procedure is wrong, especially if you put it back on the running unit and it works.

if you have a lawnboy self propelled there is a sensor on where the bag goes on mine that sensor was bad. I disconnected it and it starts right up on first pull

Rivets said:

I’m not being a smartA, but could you have installed the coil upside down? It has been done more than once.

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Lol this one made me laugh