small engine coils

Small engine coils rarely go bad or fail to function on single
cylinder engines,although twin cylinder engines seem to
have more of a problem, especially briggs.

The flywheel has a magnet attached to it in a certain spot
and as it passes by the coil,it causes the coil to charge and
send a spark to the spark plug.

There are no power wires going to the coil.The only wire on
todays engines attached to it besides the spark plug wire is
a ground wire that is attached underneath coil and it runs
through usually a safety switch circuit on lawnmowers or a
cuttoff switch on other applications.However if a power wire
gets attached to this ground circuit by mistake it will blow
the coil.Ihave seen this before, also it will smoke or burn the
hot wire that is attached by mistake.

Older briggs and tecumseh have a set of points and
condenser that are located underneath flywheel and usually
that was a yearly chore to replace points and condenser, but
todays engines use an electronic coil that does away with
the points and condenser.You also can replace old style coil
that has points with electronic coil, by simply bolting it on.

TROUBLESHOOTING COIL is simple by disconnecting
ground wire, which is usually black coming from coil,pull
plug out, spin engine and watch for spark, no spark, bad
coil, good spark, good coil assuming spark plug is good.

You can bypass safety switches with this method
also,engine wont shut off until you connect wire back
though.
Briggs coils from one engine to another as far as
horsepower wise usually wont interchange, it all depends on
the size of flywheel in bigger horsepower engines.
A SIGN of a coil going out will be that the engine will run until
it gets hot and then shutdown and when it cools will fire
back up and do the same thing,do the above test when its
hot to check for sure that it is the coil failing.Coil gap is .010
between flywheel and coil.