Kohler K9J Service Manual page 75

BRACKET-~--~
(PART OF
COIL)
- - - - - T O TRIGGER
& SWITCH
Figure 8-6. Typical Breakerless Ignition Coil.
Breakerless Ignition System Timing
Because there are no breaker points in this sys-
tem, there is no requirement for timing. However,
there is a requirement for positioning the trigger
module for proper relationship with the flywheel
projection. The gap between the projection and
trigger module is normally set between . 005 and
.010". This setting is not critical, but selecting a
.005" gap promotes better cold weather starting.
Set the gap as follows.
1 . Remove the spark plug lead to prevent inad-
vertent starting.
2. Rotate the flywheel so that the projection is
aligned with the trigger module.
3. Loosen the cap screws on the trigger module
bracket and insert a . 005" feeler gauge in the
gap.
4. Move the trigger module until it touches the
feeler gauge, making sure that the flat sur-
faces of module and projection are parallel.
5. Tighten the cap screws and replace the spark
plug lead.
The trigger module has two clip-on type terminals.
Make sure that the leads are connected as shown
in Figure 8-7.
TRIGGER MODULE (BREAKERLESS)
The trigger module used on breakerless ignition
systems is a solid state device which includes
diodes, resistor, sensing coil and magnet plus an
electronic switch called an SCR. The terminal
marked A must be connected to the alternator
while terminal
I
must be connected to the ignition
switch or ignition coil. Operating with these leads
reversed will cause damage to the solid state de-
vices. If a faulty trigger module is suspected, dis-
connect and remove the trigger from the engine
and perform the following tests with a flashlight
tester. Reset air gap when reinstalling trigger.
Diode Test
Turn tester switch ON and connect one lead to
the I terminal and the other to the A terminal then
reverse these leads--light should come on with
leads one way but not the other way. If light stays
on or off both ways, this indicates diodes are
faulty--replace trigger module.
SCR Test
Turn tester on then connect one lead to the I
terminal and the other to the trigger mounting
bracket.
NOTE: If light comes on, reverse the leads as the
light must be off initially for this test.
Lightly tap magnet with a metal object--when this
is done, tester light should come on and stay on
until leads are disconnected. If light does not
come on, this indicates SCR is not switching prop-
erly in which case trigger module should be re-
placed.
IGNITION COILS
Breakerless Type Ignition Coil
Use an ohmmeter to test breakerless type coil
assembly. (A) -- Remove high tension lead from
terminal on coil. Insert one ohmmeter lead in coil
terminal and the other to the coil mounting brack-
et. A resistance of about 11,500 ohms should be
indicated here. (B) -- Connect one tester lead to
the coil mounting bracket and the other to the
ignition switch wire. Continuity should not be indi-
cated here. Replace ignition coil assembly if wrong
results are obtained from either of these tests.
Magneto and Battery System Breaker
Points
Engine operation is greatly affected by breaker
point condition and adjustment of the gap. If
points are burned or badly oxidized, little or no
current will pass. The engine may not operate at
all or may miss at high speed. Size of the breaker
point gap affects the amount of time the points
are open and closed. If the gap is set too wide,
they will open too early and close too late. A defi-
nite period of time is required for the field to build
in the ignition coil. If the points are closed for too
long or too short a period, a weak spark will be
produced by the coil.
Figure 8-8 shows the effects of too little and too
much capacitance in the condenser. Severe metal
buildup on either contact indicates that the con-
denser is not properly matched to the rest of the
system and should be replaced.
8.5