I have a hand-start lawnmower that stopped running recently. It is a Briggs
& Stratton, about 5 yrs old, and gets medium usage. It has given me no
problems until now.

The cylinder appears to be getting a fuel/oil mix delivered but is not
getting spark. I have pulled the plug, checked it for fouling and proper
gap, and grounded out the 'outer' terminal of the plug while connected to
the plug wire and not seen a spark when cranking the engine. Finally, I
wound up jamming the tip of my little finger in the plug boot and while my
thumb was grounded to the motor head cranked the engine. No pulses into my
hand so unless somebody tells me otherwise, I am confident my primary issue
is the 'spark'.

I removed the engine covers and see an electronic device similar to the
device in the following link:

http://science.howstuffworks.com/question375.htm

My flywheel looks almost identical to that though scaled up a bit in size.
Soooooo........ I have read about coils elsewhere at that above link and am
left with more questions (from more knowledge) than I started. I have
checked the 'safety' aspects of the mower to be sure they are not
intervening (the mechanism that breaks the circuit in case you release a
lever up at the top of the handle that is required to be depressed during
operation).

1) I read 4.5K ohm between the plug wire and the engine block.

2) I have very lightly sanded the track of the flywheel the travels under
the coil poles(?) to remove some light rust on the flywheel and be sure the
gap between the flywheel and coil was consistent.

Sooooo, unless you think otherwise, my guess is that the condenser/cap of
the magneto/coil is bad. (It seems like I might still feel a little jolt at
the plug wire - just not as much as normal - unless the cap is shorted out,
but then wouldn't I read a short to ground from the plug wire?)

Anyway, thanks for your time if you have read this.

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