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Twin Briggs Won't Shut Down


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#1 chieffan OFFLINE  

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Posted September 15, 2016 - 11:05 AM

Twin cylinder, horizontal opposed, older model.  No numbers found.  Has three wires from the flywheel.  One with a diode for the charging system, another same size and location for the lights.   Charge.JPG

 

On the other side is a small black wire, has to be from the mag coil.  That small black wire goes to the insulated stud as can be seen in the photo.   Block.JPG

 

Another wire from that stud goes to the points box right in front of the carb.  The engine starts and run good. But cannot kill it by shorting out the stud of the wire from the coil.  Have run a jumper from the wire terminal from the mag at the stud direct to the ground on the battery as well as a couple other grounds on the engine.  Keeps right on running.  Never seen anything like it.  How do I get this engine to shut down short of putting an on/off switch in the place of that insulated stud ? ?

 



#2 MH81 OFFLINE  

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Posted September 15, 2016 - 11:57 AM

Shouldn't there be a wire from the points?
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#3 chieffan OFFLINE  

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Posted September 15, 2016 - 12:38 PM

The wire from the point box is connected to the insulated stud,where the wire from the mag is attached.  In the first pic the black wire with the red connector goes into the point box right on top of the engine.  Have to have connections on both ends of the wire, at the mag and at the points or it wouldn't run.   The manuals I have looked at show that stud to be the stop switch connection point.


Edited by chieffan, September 15, 2016 - 12:40 PM.


#4 Bud W OFFLINE  

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Posted September 15, 2016 - 12:43 PM

Those Briggs engines have Magnetron coils, you need to ground that stud to kill the spark. If grounding doesn't kill the spark, the wire from that stud isn't connected to the coils inside the blower housing.


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#5 chieffan OFFLINE  

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Posted September 15, 2016 - 01:04 PM

OK.  Will check that end out.  Never had to work on any with the Magnetron ignition.  I didn't think the Magnetron had points?



#6 Bud W OFFLINE  

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Posted September 15, 2016 - 01:39 PM

It doesn't, the Magnetron coils have a pulse coil in them that doesn't require points.


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#7 MH81 OFFLINE  

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Posted September 15, 2016 - 01:52 PM

So, I wonder why this engine does have points?
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#8 DougT ONLINE  

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Posted September 15, 2016 - 02:03 PM

maybe someone replaced a points coil with a magnetron and didn't hook the kill wire up? You would have to remove the point wire to hook the wire back to the stud. I don't ever remember seeing an opposed twin with points but really haven't worked on that many of them.


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#9 glgrumpy OFFLINE  

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Posted September 15, 2016 - 02:18 PM

Well, see that tab on insulated connection! THAT needs a wire from your key switch that goes to ground hooked to it. For a test, run the engine with a wire connected to that tab and touch anywhere to a ground and should kill it. The key needs to have the M terminal on it for Mag, that is the kill wire. Is there an extra wire floating around near there off a harness?   Might have to follow wire from switch to see if cut-off somewhere or just not routed and connected. This is assuming is orig to tractor?  If not, a kill switch of your own on dash and down to that tab, and other term to ground will be needed.


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#10 Bud W OFFLINE  

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Posted September 15, 2016 - 03:03 PM

Those Briggs engines don't have points!


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#11 MH81 OFFLINE  

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Posted September 15, 2016 - 03:27 PM

Those Briggs engines don't have points!


I read that, but in his original post, he says there is a points box. I made the natural assumption that it wasn't empty, especially when it was stated there was a wire going in there.
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#12 chieffan OFFLINE  

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Posted September 15, 2016 - 04:51 PM

I did not take the cover off the points box but there is a wire going to it and the cover is sealed.  I didn't want to break the seal just to see what was in there as it is a running engine.  So if it don't have points - why is that wire there and what does it do ? ? ? 

 

To solve the problem - the engine had been apart or at least the flywheel has been off.  The female terminal that goes to the tab on the mag was along side the tab instead on on it.  Put it on and it works.  3 hours work just to put a wire on a terminal that somebody forgot.  Could not have been put on as there were wire ties holding the two plug wires and the kill wire together.  No way it could have worked off.  Any way - problem solved.  Thanks for all the help and education.  Still not sure if it has points or not but really don't care as long as it keep running. 

 

To add to the confusion, when I put a test light connected to the stud and to ground, it will read continuity but when the flywheel is turned just a little the continuity goes away.  Acts just like points, when they are closed the circuit is grounded.  When the points are open, no ground.


Edited by chieffan, September 15, 2016 - 06:53 PM.

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