Kinda burning your bridges that way aren't you? What happens if the machine is in the boonies somewhere and its battery goes low-or gets too weak from cold to start the engine as it declines?
Well, you may have been right all along about the no start with no clearance on the valves. AND it looks as if you're right about the wisdom of using an "official" (or at least adjustable) type of spark plug tester too.
Now it looks as if 2 (or more) different things are probably going on here at the same time. The valve clearance issue AND the ignition-related issue. At least.
Today I tried unplugging the alternator wiring and that made no difference-there was still a momentary flash of what looked to be a low voltage to the killwire when turning the old ignition switch from run to off. (Not from a running engine to off. )
I got sidetracked before testing the NEW ignition switch, because right about then while digging out some ar compressor accessories to inflate a flat tire on our driveway, I finally found my "official" (adjustable gap) spark plug clip on tester, and just for hell of it (after the tire) clipped it onto #1 spark plug lead with the same (new) Magnetron installed that I'd thought had completely cashed in. No spark-until I closed the gap down to about .030. Then there was a spark. ( Maybe the coil is only weak but at least it's still got some life left.)
I double checked the flywheel air gap and once again ran into the same dilemma that I've had for some time-which I probably should have mentioned earlier-a LOT earlier.
I ALWAYS set the gap with both legs of the Magnetron simultaneously straddling the flywheel magnet, (which has them overlapping the adjacent body of the flywheel on both sides on this engine) but when I do that I have a choice between setting the gap while letting the feeler gauges cross the entire face of the magnet and overlap onto the flywheel OR set the gap while ONLY letting the feeler gauges lie between the magnet and the Magnetron. Never read anything that indicated it would be a problem either way. So, I've been under the assumption that it shouldn't make a difference, because the air gap is supposed to be between the magnet and the legs.
The dilemma comes up because on this particular flywheel, the face of the magnet is very slightly crowned (higher in the middle and slightly lower at the outboard edges where the Magnetron lines up with it when it's being set.).
In addition to the crowned configuration, at the magnet's outboard edges it's actually several thousandths of an inch below the adjacent front metal surface of the flywheel.
So, if I set the air gap while the feeler gauges are overlapping the body of the flywheel it's several thousanths wider than if I set air gap while holding the feeler gauges so that they lie between the magnetron and only the magnet. In fact, currently doing it the second way allows the Magentron to scrape the flywheel's light coating of surface rust ever-so-slightly at a couple of places around it's perimeter when that gap is set to specification.
I'd been setting it to the "no-scrape" result-until today.
After seeing that spark in the spark tester when it was set at well under what Briggs official one's gap is supposed to be (.070" I think) , I closed the armature air gap down slightly. It was now .010-but in the flywheel scraping position. The gap in the spark plug tester could then be opened up quite a bit-it was now jumping a gap of about 1/8" possibly more-while cranking....hmmm.
Leaving plug wire #1 loose, I swapped the spark plug tester over to cylinder #2 and reconnected the alternator wiring,and cranked the engine again-good 1/8"+ spark on that one too.
Reconnected spark plug wire #1, cranked and the engine didn't start. Hmmmmm
Went over to #2 cylinder, reconnected that wire too and the engine started. DOUBLE hummmm.
DISCONNECTED #2 spark plug wire-no start. Aha.
Either it's the phase of the moon, or the barometric pressure, and this will be completely different tomorrow-or it's starting to make sense.
#1 cylinder is the one who's head I'd pulled 2-3? weeks ago and had noticed the valve being able to spin when it was supposed to be seated.
So it looks as it cyl #1 NOW is not firing while starting, so maybe I co-incidentally cleaned the seat areas too well on #1- and the intake valve is even looser in the seat no than it had been. And that the air gap has to be set so that the armature is scraping the flywheel in order to start.
I've been doing almost all my SPARK checking from the cylinder #1 accessible side where the armarture is on this engine (with the inductive timing light.) So maybe cylinder #2 had actually been getting combustion more of the time, and the engine was runnning on one cylinder part of the time lately-which might have helped overheat things and helped do in the armature? Neither plug ever seemed either burnt or badly fouled.
Now I'm wondering, if the flywheel magnet can be shimmed, maybe I could raise it and eliminate the scraping while keeping the proper gap. I see what looks like a flush Phillips screw recess in the center, but don't know if that is anything which can or should EVER be unscrewed-but I'm not going to try doing that before getting more info.
Have you ever heard of a flywheel magnet being like this on a 18.5hp or similar Briggs, and is there anything that could be done to rectify that besides shimming the magnet, replacing it, replacing the entire flywheel or or turning the flywheel on a lathe to even out it's surface? I still think that a GOOD armature would be able to jump a wider gap than .010", but it would be nice to be able to set it correctly and not have the scraping.
Luckily it's been raining here, so I wouldn't have been able to mow much lately.