Engine System
32
Service Manual – PBU Propane Floor Burnisher
Ignition Coil
Troubleshooting
The ignition coil is self-contained with no serviceable
components So troubleshooting should be limited to
pass/fail and component replacement Contrary to
intuition, the ignition keyswitch does not provide power
to the ignition coil Instead, the keyswitch grounds
the coil circuit when the engine is not supposed to be
running, and opens the circuit (no connection) when the
engine should run Therefore, the two failure modes of
the ignition keyswitch wire are as follows:
• Short to Ground: Engine never starts
• Open Circuit (or short to positive): The engine doesn’t stop normally, because the coil circuit would not
be grounded when keyswitch is turned off (The engine would still stop because fuel is shut off at the
fuel cutoff )
1 To check whether there is a problem (short to ground) with the ignition (keyswitch) wire, unplug the
wire from the coil and see if the engine starts If the engine starts only when the wire is disconnected,
then trace the wire to look for a short to ground
Caution:
Do not touch the spark plug wire while
cranking the engine or you will likely
receive a shock.
2 With the fuel service valve closed, check for spark by
cranking the engine for no more than a couple seconds at
a time:
• If an ignition spark tester is available, connect one end
of the spark tester to the spark plug wire and the other
end to a good ground Crank the engine and look for a
spark at the tester
• If an ignition spark tester is not available, use a fresh spark plug, connect it to the spark plug wire and
use a jumper wire to ground the metal base of the spark plug Crank the engine and look for a spark at
the tip of the plug
3 An alternative check for the coil is to measure the coil resistance
• Secondary Winding: Between the spark plug wire and ground (S & G) should be 10 - 20 k
Ω
• Primary Winding: Between ignition wire
and ground (K & G) should be 3 -13 k
Ω
• Both Windings: Between the ignition wire
and spark plug wire (K & S) should be
between 18 - 28 k
Ω
4 If the ignition coil does not generate a
spark, replace the coil as described below
5 If the ignition coil produces a weak
spark, the check/adjust the coil air gap as
described below
6 If neither cylinder has spark and both coils
are deemed good, then the flywheel is bad.
Spark
Coil Wire
Ground
Jumper
Tr
igger
Keyswitch
S
G
K
Magnet
S
N
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