QuestionQUESTION: Tecumseh HM100 No spark visible on good exposed proper-gap plug. Wires look good. Cutoff switch checked with meter OK. Suggestions ??
ANSWER: To test, the metal body of the spark plug must be touching a metal
part of the engine {grounded}.
If not, remove the top cover, and look at the coil, make sure
the spark plug wire is not chewed up near the coil{mice, etc..}.
If not, unplug the small wire plugged into the coil, then put the cover back on again and test again. If you still have no spark,
then the coil is bad, providing that your test spark plug is good.
If you get a spark with the small {kill} wiire disconnected, then you have trouble elsewhere. These ignitions work when the
flywheel passes by the coil, then it produces a spark, unless the
coil is grounded, like by the on/off switch.
Follow the small wire to whereever it goes, make sure there are
no bare spots in the insulation.
Look to see if the wire goes elsewhere, like to a low oil shutdown,
you might just be a tad low on oil.
Take a look and see, and let me know what you find.
---------- FOLLOW-UP ----------
QUESTION: I put sprkplug in metal vicegrip & rested that against metal of engine: is that sufficient ground? If low oil shutdown switch is defective, should removing wire let spark occur? Is mild rust on flywheel a hindrance? Is there a capacitor or similar in/at coil?
AnswerYes, that should be good enough ground. Disconnecting the little kill wire at the coil takes everything else out of the loop.
Rust on the flywheel won't be a problem. You might remove the coil and sand where it bolts on the engine, as that needs a good
connection. If all else is as I say, then the coil is bad.
There is no electric start, or anything like that, is there?
