# briggs 12hp spark polarity?



## russwr1 (Jan 9, 2011)

How do I change spark polarity on the ignition coil output for positive spark and negative ground? Does the flywheel magnet have to be reversed?


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## Basementgeek (Feb 7, 2005)

Hi and welcome to TSF

I guess the question on anybody mind is why you would change it if it could be done.

BG


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## jrrdw (Jun 26, 2010)

Do you currently use a positive ground? 6 volt system? Mind if I ask what country you are in? If you are in the USA, where did you get the mower? We also need the make and model, model number and serial number and engine numbers to help you.


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## russwr1 (Jan 9, 2011)

*Change spark polarity?*

12HP briggs engine, 1 cylinder, model 281707, type 0155-01, code 87092911.
Looking to change negative spark to positive spark on bench mounted engine.
The flywheel magnet won't come off to reverse it. Tried torch heat and impact wrench + sledge hammer on center screw. The regular magnetron coil won't fire upside down because of module transistor connections. The briggs 12hp was tested with tv high voltage stick rectifier to verify negative spark output. I will be testing retrofit MAGNETO with module for solid state with upside down mounting. The engine has no provision for using points.

Experimenters are using diode from microwave oven to increase spark power on the other battery type ignition coils by mounting from low V Plus to high V plus and cathode band facing high V.
I surmise this technique was used by Georgia man on his 2008 water conversion 18hp briggs, along with hand wound transformer .(Nathren said he made no engine changes- negative spark , and only used special wound coils assembly to deliver increased current to plug) The water changes with LARGE SPARK to water vapor pressure and runs engine, as long as coil inductor is in series with spark plug to lengthen time in milliseconds for contact of arc with moisture. .The added diode conversion requires positive ignition IF he used it. I checked this sparking myself on work bench as much larger spark on car coil and cycle coil.
You can see water sprayed on (modified ignition) fired spark plugs making big bangs on you tube videos. Others are firing plastic syringes with water, 2 contacts and capacitor discharge, with cylinder plug shooting across room. Some machine shop operations use water tank with submerged fixture , sheet metal just above, and upper spark gap which is fired in water so the metal is formed over fixture with pressure wave - called electro- hydrodynamics.
See also Nathren's 2008 engine You Tube videos- as Video ! , Video 2 from S1R9A9M9 .His website is on Yahoo, under GROUPS, as Watercar1978.- files, and back messages.
I know all about this data from previous study, and the science journal reference called" the release of intermolecular bond energy of water".


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## Basementgeek (Feb 7, 2005)

I suggest that you continue your google search on this, what I consider, off the wall claims.

I actually tried to burn water, is does not burn. I too saw some you tube videos on the subject.

BG


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## jrrdw (Jun 26, 2010)

If you were using this for it's intended purposes I would be glad to help you. This is beyond my intrest, good luck with your project.


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## russwr1 (Jan 9, 2011)

A while back, I changed the 12HP Briggs ignition over to positive high voltage , rather than negative 10kv to positive ground. I removed the magnetron, replaced it with a NEW, (pre 1982 old style), magneto coil, inserted the optional s,s, module on opposite side of core leg, and mounted the NOW "magnetron" upside down with large rivets facing up. With engine started, polarity can be checked with high voltage diode, and also the spark jumps downward now. High voltage is a little bit less this way, but testing is done for the S1R9A9M9 conversion as on You tube videos. I am currently making curved 1/8" alum plate adapter to move ignition coil over , to change to later timing.
Mechanics on forums say that timing can also be changed by removing the flywheel key, doing the lapping compound on crankshaft sticking up, and the matching center hole on flywheel. The flywheel is reinserted , no key, and tighened with lockwasher( instead of flat washer" + nut in different position on crank. The other offset keys are only made for those tiny racing Briggs engines.


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## Basementgeek (Feb 7, 2005)

2 year old post

BG


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