IGNITION SYSTEM
55
Flywheel
The flywheel holds the magnets. These magnets
induce a field in the module which in turn produces a
spark. It also controls the timing of the ignition system
by controlling when the magnets are introduced to the
module.
A sheared flywheel key will throw off the ignition tim-
ing. Sheared keys are uncommon on MTD engines. If
one is found, check the crankshaft and flywheel for
damage. To Remove and/or inspect the flywheel and
key:
1. Remove the blower housing.
1a. Remove the engine shroud by following the
steps procedures in Chapter 3: Air Intake
Systems
1b. Remove the front fuel tank shroud using a
10 mm wrench.
1c. Remove the five screws securing the blower
housing and slide it off of the engine.
2. Block the piston to prevent the crank shaft from
turning by:
2a. Remove the spark plug.
2b. Insert approximately 3.5 feet of starter rope
in the spark plug hole.
IMPORTANT: Leave part of the rope sticking out
of the engine so that the rope can be removed
later.
3. Remove the flywheel nut, starter cup and fly-
wheel fan using a 23mm wrench.
4. Remove the flywheel by applying a sharp blow
to the crankshaft using a brass drift punch and a
hammer while gently prying with a prybar. The
flywheel will loosen then lift it off.
NOTE: The magnets on the inside of the magnet
will hold it down, preventing the typical “pop”
when the flywheel loosens from the tapper on
the crankshaft.
NOTE: Never strike the crankshaft directly with a
hammer. To prevent damage to the crankshaft
use a brass drift punch or a piece of wood
between the hammer and the crankshaft.
See Figure 7.14.
Figure 7.14
Brass Drift
punch
! CAUTION! CAUTION
If the flywheel shows any signs of
physical damage such as cracks,
broken vanes, or damaged key-
way, replace it. A damaged fly-
wheel poses a threat of burst fail-
ure. Burst failures are extremely
hazardous to surrounding people
and property.
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