S1R9A9M9 - AC Inverter Box Not Used On Briggs Mower Engine 2008 ?
There was another small mystery regarding the S1R9A9M9 web forum and You Tube videos on why the 110v AC Inverter box was not used on the last electrical conversion for the Briggs mower engine. All earlier car engines conversions in Georgia had used same inverter box and same set of special relays transferred to each vehicle. Statements were made as it could not be used on the Briggs 18Hp even though it was also a 4 cycle type. It rather bugged me, and I had set aside the notion for later on. After many design types of S1R triple coils that I made over a period of years tinkering, I surmised that the ORIGINAL triple S1r coils that you saw in Internet photos MAY NOT of also been the only one. Many people wrote in and complained about the original bare wire the High volts went through. I just assumed Nathren was too lazy to build it right, even though it still worked. Most people know that engine conversion that uses hydrogen requires LATE timing. All the earlier cars in Georgia had the distributor turned so that late timing was about 34 degrees ATDC. The Briggs lawnmowers have mounted ignition coil called Magnetron that does not move. That's what one of the purposes the magnetic triple S1r wire coils was for - to force extend the spark ON TIME so as start fire at zero on to near -34 degrees shut off. Nathren, in the Georgia shop knew about the necessary timing change , and had built this triple coils in conjunction with an inductor as was also used on the car engines that was  inside the relays, for further time extension.  So here comes the answer!
 In the 2008  2 videos, the AC 400watt Inverter Box and Power clips are on the ground not electrically connected, and brown extension cord is seen in background. He did say they were not used for the lawnmower demonstrations of water in carburetor. These things were just left there in the videos after initial FAILED Box tests, and were not removed as they should be before the final You tube filming. The series resistance of spark plug firing of auto engines tested 2005-2013,  had about 1.4 ohms of the 2 coils in the relay per cylinder from approximately 43Volts half wave DC source power. There were voltage drop losses from the several diodes in circuit. The spark plugs were changed to cross reference to near zero ohms spark plugs without the R in code, instead of 6000 ohms. Pulse peak current on garage oscilloscope was 6-7 amps. Now, the 18HP Briggs normally used 4000ohms spark plug. The one chosen as replacement used was long reach QC12YC  as 125 ohms. The "Smack" You Tube follow up videos showed the same engine with this 2nd spark plug. Engine needs what's called long reach threads type, and they, probably in 2008, could not get a zero ohms replacement spark plug. Based on Ohms law formula, I X R = Voltage required, 10 A X 125  ohms is 1250 volts . The 60 cycles inverter output DC after diode is only around 40 volts. Inverter could only produce about .3 amp. (not 10A). I SURMISED that there was another FIRST S1R coils assembly that had ALL insulated triple wires. After the Box test failure ,  a 2ND triple coils was put together to make use of cross leakage induction of High V from BARE COPPER WIIRE into the insulated low voltage side  to raise up superimposed voltage from battery over 12v to be able to get the 10 amps for the Briggs firing of spark plug, for more Hydrogen fuel generated. He said to vary the number of turns for varying magnetic field over the plug wire so as point is reached for smoother running. (At that time period 2008, he may not of known that the Champion brand spark plugs as cross reference can COME APART to remove the high resistor and get a zero ohms racing plug. )
Therefore,.... if proper zero ohms spark plug was used on 18HP engine with in series other parts, and more "highly"  insulated wire cables are on magnetic coils, then the Inverter box of about 40volts DC could actually have been used, instead of the direct 12v car battery in the 2008 demonstrations. The high voltage also probably interfered with the 60 cycles circuit output of inverter and bogged it right down. There was no set of 10kv protection one way series diodes in the circuit.  He said the plastic tub on side of engine also contained other parts besides the triple coils, as accessory spark gap, rectifier diodes, Inductor, for use with the dual alternators on the engine under the flywheel. 12 Magnets ran the charger output underneath flywheel for free power when crankshaft was turning. When battery was completely removed, the engine ran on both alternators output as self sustaining (over unity) performing electrolysis in spark plug chamber. Nathren was in general, a non technical person contrary to the 2 techs working in the shop. The WaterFuel1978 Yahoo Groups web forum of statements, tech questions and answers, was shut down, mostly because a further source to purchase of the exact relays could not be found. That's why a parts list was not given to the public. See again the S1R9A9M9 (2) You Tube videos of lawn mower engine actually running on water to hydrogen + water vapor pressure. It sounds like a water pump!