Unusual B&S?

At the Dallas show, (Cotton Ginning Days), ran accross this model ZZ with 2 spark plugs. Is this rare? What was the reason for 2 plugs? What kind of coil(s) points setup does it use?

BTW, I missed Ray Medford, he was there for only a short while but Mrs. Medford said he is doing just fine, Ralph in NC

Ralph:

I'm with you - I've never seen a two plug one-lung Briggs. I suppose it was done to make the engine more reliable, like in fire service.

The coil for firing two plugs isn't really too special. Instead of grounding one of the high voltage leads and running the other to a single plug, they didn't ground the first lead but brought it out to a plug wire.

If you think about it, the circuit will work fine and does on Harley twins, opposed 2-bangers like Onan and inline 2-bangers in which both pistons move on the same crank throw.

How it works is, the high tension output from one lead of the coil goes to one plug, across the gap of one plug, through the frame of the engine, across the gap of the other plug then back to the other high tension lead of the coil.

Hope this 'splains it.

Take care - Elden

Thanks Elden, I never considered a series ckt. I was guessing a grounded center tap and 2 plugs in parallel. Just when you think you've seen it all, something like this pops up, Ralph in NC

I was working on a B&S Model B today and noticed that the spark plug, which also is in the side of the head, actually fires in a little precombuation chamber that has a hole that leeds to the top of the piston. Maybe the two plugs has something to do with the timing of the start of the flame front or fronts for combustion. I assume the plug on the top fires directly in the area above the piston.