On Fri, 24 Jun 2016 20:44:02 +0000, Marc Belanger
wrote:

replying to Sherman, Marc Belanger wrote:
The lawn mower is probably losing spark. It will get good spark if it is cold,
but once hot, one of 3 things could be happening. First, the spark plug could
be filled with crud, and when it is cold, the crud has a lot of non conductive
grease in there. This will turn to a liquid when hot and become conductive
enough to short out the coil pack and kill the spark.


Less than 1 chance in 10,000,000 of THAT being the problem. Spark
plugs and infewrnal combustion engines don't quite work that way.
I would replace it if it
looks like there is crud between the edge of the steel and the porcelain on
the inside of the spark plug. Look between the metal electrode and follow the
porcelain where you can't see it anymore.. Yeah, thats the place, either clean
it out and get the bl;ack stuff out, eliminating the short and it will
probably work again. if not, the spark plug wire may be cracked and work while
cold, but once it warms up, the break is separated enough not to work.

Again you are picking at straws - with something perhaps in the
nieghborhood of a 1 in 5,000,000 chance.
Same
thing with the coil.

Now you are gettind somewhere close to the realm of possibility - and
even probability. The coils have solid state components in them that
can fail from heat and vibration.
The FIRST thing to do is remove the shroud and blow all the chaff and
weed seeds out of the cooling fins to make sure the engine is
cooling..Re assemble the engine - run it 'till it quits, pull the plug
wire and hold the end of the wire while someone gives the rope a quick
pull. If your eyes don't light up, you KNOW it is a spark problem.


Or, the coil could be hust loose. It needs a ground to
work and if the coil is loose, when cold it may be connected electrically then
when it warms up it may disconnect.
Generally, if the coil is loose it will hit the flywheel and it is
more likely to have a problem starting cold than hot.
The coil and spark plug wire are one piece
on a tecumseh or briggs and stratton and are less than 25 bucks normally. Get
one, screw it on, wire it and rreplace the spark plug. Then, check to be sure
the shut off wire isn't shorted to metal anywhere, it it is, the mower will
still not start.
Why not check that first, and quite possibly save yourself 25
bucks??
tape it or reconnect it correctly to fix. The coil is under
the crankcase cover.

And in many cases (all older tecumsehs ) under the flywheel too.

Oh, btw, the coil needs to be mounted the correct
distance from the flywheel if you never seen one before. Try to line up or
mark the old one before loosening it. Some coild only mount in one location so
this may not matter.
On a Briggs (external mounted coil) a peice of cigarette package
cardboard or a business card is "close enough for government work".