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Briggs coil question

#1

I

imchucky

I have a 135212 5hp on a chipper, and am not getting spark.
I ohmed out the coil and it was low, so I ordered a new coil.
Now the part that has me confused. I also have continuity between the kill wire terminal and the frame of the coil on both old and new coils, so the termial is a ground as soon as I bolt on the coil. I've tried cranking it with the wire connected and disconnected, and still no spark.
I set air gap to .013 and even tried .010 but still no spark.
What am I doing wrong?
Now the next. The kill wire attaches to the throttle control and provides a ground when moved to the off position, but the second wire coming out of the plug is screwed to the carb. Wouldn't this ground out the kill terminal all the time?


#2

tom3

tom3

Usually the carb has a sliding contactor that connects that wire to ground when the throttle is closed. The wire connection should have a couple fiber/plastic washers to isolate it from the metal bracket.


#3

H

helomech

Depending on the coil you might have to spin it over pretty fast for it to fire. On my chipper if you don't pull it fast enough it will not fire. From the briggs pdf. NOTE:Flywheel must rotate at 350 RPM
minimum on engines equipped with
Magnetron ignition.


#4

I

imchucky

Usually the carb has a sliding contactor that connects that wire to ground when the throttle is closed. The wire connection should have a couple fiber/plastic washers to isolate it from the metal bracket.
Thankyou.
Yes it does, but the second wire is already grounded to the carb, and due to the continuity through the coil.
, if I check the continuity through the coil, if it is installed, it already has the kill wire terminal grounded even without the wire connected.
Am I missing insulators for the mounting screws or something?
Unfortunately this came to me with fuel issues, so I never cranked it to see if it even ran until I cleaned the tank and replaced the carb.


#5

I

imchucky

Depending on the coil you might have to spin it over pretty fast for it to fire. On my chipper if you don't pull it fast enough it will not fire. From the briggs pdf. NOTE:Flywheel must rotate at 350 RPM
minimum on engines equipped with
Magnetron ignition.
Thanks. I'm pretty sure I'm pulling it fast enough, as this is not my first chipper, unless I've gotten really weak in the past few years LOL but I don't understand why the kill wire terminal shows ground when the coil is mounted even with the wire off.


#6

tom3

tom3

All those wires don't do anything to make the engine run, just to shut it off. Disconnect all of them at the old coil and see if it runs. Nothing to lose at this point. You can always kill the engine with the choke at idle.


#7

McB

McB

Are there any other safety switches/sensors/ on this model? if one fails it will send the coil output to ground and result in less spark or no spark. Also, check the connection at plug. I have seen the cover separate on the inside


#8

B

bertsmobile1

Inside the coil is a Hall Effect trigger chip.
This replaces to old points & capicitor system.
So measuring the ohms on the primary circuit is totally meaningless and some cheap meters can actually destroy the chip thus rendering the coil junk.
Because of the embedded chip, a lot of coils are handed so must be installed the right way round and again a cheap coil is usually destroyed if fitted upside down.

The only testing of a coil you should do is the secondary , laminations to plug cap.
Forget about the primary.
As for the connections the wire to the kill tab must be open circuit for the coil to work and closed to ground to stop the engine.


#9

I

imchucky

All those wires don't do anything to make the engine run, just to shut it off. Disconnect all of them at the old coil and see if it runs. Nothing to lose at this point. You can always kill the engine with the choke at idle.

Thanks Tom. I understand the wires are just to kill the ignition, and I tried cranking it even without the plug connected. That is when I discovered the terminal was grounded as soon as I bolted the coil on.
I have since ordered a genuine Briggs coil and returned the Oregon coil that when I tested, had continuity between the mounting surface and the terminal for the kill wire.


#10

I

imchucky

Are there any other safety switches/sensors/ on this model? if one fails it will send the coil output to ground and result in less spark or no spark. Also, check the connection at plug. I have seen the cover separate on the inside

No sir, no other safety devices, just the throttle control.
I DID notice that the second wire coming from the kill wire pigtail is directly bolted to the carb which confused me, so that is what made me try unplugging it in the first place.


#11

I

imchucky

Inside the coil is a Hall Effect trigger chip.
This replaces to old points & capicitor system.
So measuring the ohms on the primary circuit is totally meaningless and some cheap meters can actually destroy the chip thus rendering the coil junk.
Because of the embedded chip, a lot of coils are handed so must be installed the right way round and again a cheap coil is usually destroyed if fitted upside down.

The only testing of a coil you should do is the secondary , laminations to plug cap.
Forget about the primary.
As for the connections the wire to the kill tab must be open circuit for the coil to work and closed to ground to stop the engine.

Thankyou Bert, and I am not surprised when you say cheap meters can ruin it, but I have been an automotive tech since 1986, and when it comes to electrical especially, I try to use only the best... In this case being a Snap On DVOM.
Still, I will heed your advice and just install the new Briggs coil when it arrives without testing the primary side and go for it.


#12

tom3

tom3

One other thing, rare, but it happens. Check the flywheel magnet strength. Let a screwdriver hang with two fingers by the handle about 3/4 inch away from the magnet, it should pull in easily. If not you might need to find another flywheel.


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