It may not have any electronics. On a Sears mower that I have, I had a no start
condition and I made the same discovery you did. What I also found, though, was
that as a result of hitting lots of rocks and other obstacles, the flywheel had
sheared its key somewhat and was now out of correct timing range. Apparently,
there is nothing more than a magneto operating there, with the timing determined
by the proper location of the flywheel magnets against the coil alone. I saw no
trace of electronics.
I put a proper key back in and it started first pull.
So, if there are no electronics, testing consists of continuity checks.
Anyway, that's what mine was. The parts manual refers to this coil and stuff as
"solid state ignition." While technically true, I suppose, it wasn't what I
expected.
Marc Siegel wrote:
> My lawn mower wont start. It appears theres no spark. Its an older MTD
> mower with a 4hp B&S Quattro (10A900) engine. I figured its either points
> or condenser, and pulled it apart, popped off the flywheel, and guess what
> No points or condenser. Did a little snooping on the net and found it uses
> a combined unit consisting of coil, electronics, plug wire, and it only
> costs about $40.
>
> Is there anyway to test these units? I dont really want to drop $40 to find
> out that I didnt need it. This mower is pretty beat up, but might have a
> year or two left in it
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