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B&s Model N With Dual Magnetos?


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#1 Bruce Dorsi OFFLINE  

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Posted August 16, 2014 - 09:23 AM

I was browsing through some old B&S parts manuals and see that there was a B&S model N engine made having dual magnetos. 

 

It uses the same #29617 armature, #29667 points, and #29861 condenser as the common model N, but uses two of each. 

 

Is anyone familiar with these dual magneto engines, or can provide a reason for them?

 

Longer spark duration?  ....Redundancy? ....Reliability?  ....Military application?

 

Thanks!

 

 

 

 



#2 DougT ONLINE  

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Posted August 16, 2014 - 05:27 PM

I've never seen one. Was the flywheel special? Did it use 2 plugs? I know there was a lighting circuit in the doodlebug engines but never heard of this.



#3 Bruce Dorsi OFFLINE  

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Posted August 16, 2014 - 06:58 PM

I've never seen one. Was the flywheel special? Did it use 2 plugs? I know there was a lighting circuit in the doodlebug engines but never heard of this.

 

Doug: 

 

1 Plug, ...Same cylinder head,  ...Same flywheel, ....But 2 plug wires.

 

It appears the dual ignition (Magneto Assy # 290905)  set-up was only used on Type # 205756.



#4 DougT ONLINE  

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Posted August 16, 2014 - 07:18 PM

Interesting! I'll have to see if I can come up with a picture of it. Would it be something that would change the timing? It seems that you couldn't fire the coils at the same time with the same flywheel.



#5 Bruce Dorsi OFFLINE  

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Posted August 16, 2014 - 07:32 PM

Interesting! I'll have to see if I can come up with a picture of it. Would it be something that would change the timing? It seems that you couldn't fire the coils at the same time with the same flywheel.

 

One coil is mounted in the usual position.  ....The other coil is mounted at approximately the 3 o'clock position.

 

The coils would not fire at the same time, but sequentially.   ....The "usual" coil would fire first, then the other coil would fire after approx 90* of crank rotation. 

 

I'd love to know the reason and application for this engine!


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