Kohler K91 Service Manual page 74

H I GH T E NS I ON
Fig u re 8-4. Typical Battery I gn it ion Coil .
Battery I gn ition Service
Single Cyl inder Models
Ignition problems and poor performance on these
models are often the result of using an incorrect
ignition coi l , spark plug , or plug gap setting . When
replacing an ignition coil always use the genuine
Kohler replacemen t . Use of the correct spark plug
and gap setting is also important . The specified
plug is a Champion H 1 O/RH1 0 , or equivalent,
gapped at . 035 " ( . 9mm) . Failure to follow these
recommendations will result in erratic high speed
ignition m isfire or cutting-out under load .
AC W I N D I NG
(ON STATOR )
Figure
8 . 4
�EGATI VE
- / TE RMI NAL
TO CONDENS E R
&
POI NTS
MOUN T I N G
BRACKET
1 0 - 1 6 H P
-
2
D I OD E
1
D I OD E
Of
8-5. S c hematic Typical Breakerless Ignition Syst e m .
Breakerless I g n ition System Operation
The breakerless ignition system operates on the
same general principle as the magneto system but
does not use breaker points and conventional igni­
tion condenser to time the spark . A trigger module
containing solid state electronics performs the
same function as the breaker points. Refer to Fig­
ure 8-5 .
The breakerless system consists of fou r major
components :
•
Ignition winding o n alternator stator
•
Trigger module
•
Ignition coil assembly
•
Flywheel-mounted t rigger
The ignition winding is separate from the other
windings on the alternator stator. It functions like
the magneto winding . The trigger module contains
three diodes, a resistor . a sensing coil and mag­
net and an SCR , a sort of electronic switch . The
ignition coil assembly includes a capacitor and a
pulse transformer that serves the same purpose
as the ignition coil in other systems . The flywheel
has a projection that triggers ignitio n . Refer to Fig­
ure 8-6.
In some applications a 2 2 ohm. 1 12 watt resistor
has been placed between the key switch and the
ignition coil . This has been added to prevent cur­
rent feedback through a dirty or wet switch . This
feedback, if not held in check by a resistor, can
damage the trigger u nit .
CAPAC I TOR