You know the old saying, - go back to the source, the horse's mouth. I had revelation today regarding this 2008 conversion. The Nathren 2 page write up as poorly written, can be taken in small sections for "decoding". The untrained man describes things as he sees it, not in proper technical words. I'm pretty sure I got it now.
The earlier car engine conversions with water in carburetors, were all done the same way. Lower quality Inverter box power, and "special" relays containing inductors and diode in SEALED chamber. The distributors were readjusted for late timing , about -34 degrees,use with Hydrogen gas, along with water vapor. They all used 2 car batteries and the alternator charged up both with engine running. I would consider that self running.
It always occurred to me that the mower engine was done same way. Inverter was concealed under cement block and s1r coils assembly in the plastic tub. The 2 alternators on board with output about 15 amps was to run the whole thing as self running. You said to use Grok AI for questions. I found out the Briggs alternator specs is rated 15A at very high rpm at idle speed for current output. It's really only about total 8 amps at 14v, at lowered idle rpm. This value is only good for just running the electromagnet / Megatran. (not Inverter too). Therefore, not self-sustaining when using Inverter, as also large battery would be needed buried under cement block, along with Inverter box of decent power.
Three references were found regarding greatly increased high voltage output of Briggs Magnetron, way higher than car engines coils. That's the Tesla Patent circuit added as Inductor to Briggs engine. The web forum had mentioned an inductor taken from relay to use on a project. The web forum talked about Georgia technicians doing bench tests on high volts and just water vapor.
So here goes, - I wondered about where the coil turns came from out of the blue. These are Fibonacci numbers sequence. Ratio 1 : 1.618. So my new coil will use 5,8,13, 55/or 144turns. The Triple coils is now a QUAD Step up voltage transformer and electromagnet same time. The core is full circle flux. There is extra wire from ground through protection diodes to point of Hi V entrance. This now forms a secondary useful winding. The step up volts ratio also allows small superimposed current onto the ignition line. "Must overcharge the ions of water vapor in same polarity to put in repulsion PRESSURE for piston." The voltage level secondary has to be higher than the bank voltage loss of diodes to keep them ON. Nathren called it a transformer coil. (but not a step down volts transformer) There are other small parts in the plastic deli tub hanging on side of engine. This engine is now, probably self sustaining, not having to power large inverter box.
The 150 volts comes from the step up turns ratio on same electromagnet, as extra winding. This means the original shown photo on graph paper was not one used on 2 successful videos of 2008 .
The Briggs alternators provide 8 amps PULSING DC with 2 lines together through 1 diode, low frequency around 50 cycles. In his report, Nathren called this "coming in at a waveform " to the Triple coils. He said no associated Inverter used, as the 60 cycles causes interference with the alternator output and Electromagnet bogs down, won't run.
We know the car conversion needed over 100 volts to overcome the high resistance of the tiny electrodes in water solution. This new CHANGED design by Georgia shop technicians is only looking for high volts, not current to make hydrogen gas. Completely different methodology for mower engine than the CARS. Piezo spray of fine water vapor particles is probably warranted for the carb.
There were back in 2008 -2011, a huge number of people wanting to know how this engine ran on water. I was one of them, hanging on details and doing research. Of course, an adjustable curved aluminum 1/8" plate with inside cut out curve, and drilled holes, could be machined for moving timing of mounted Briggs Magnetron. Then, the Inverter box can be implemented. The series Inductors provided the required magnetism for plug tips. (learn something every day)
Bench test for just S1r coils is digital display module adjustable for freq + duty cycle, to Mosfet on heat sink, to metal power resistor load through the coils. Meter watched to set amps on the gauge, while pushing set buttons. Magnetic field of max 8 amps worth, can be reduced in current by doubling, tripling the wire turns, and still get the same magnetic field. This can free up amps for another use, such as small inverter, like the car cigarette light plug in inverter 110v AC. . Pulsing DC is similar to the same output from lawn mower alternators. Pulsing will run a transformer, not straight DC. .
Please write back so I know you read my write up.