Kohler Courage SV710-740 Service Manual page 60

There are three different types of ignition systems used on the Courage twin cylinder engines. All systems use
an ignition module which energizes the spark plug. The difference in the system is in the way the ignition timing
is triggered.
The Fixed Ignition System utilizes a Capacitive Discharge (CD) coil (See Figure 7-3). This is a basic ignition
system that uses a fixed ignition module where the ignition timing and spark remains constant regardless of the
engine speed.
The Digital Spark Advance Ignition (DSAI) System (See Figure 7-6). This system uses a digital microprocessor
which is located in the ignition modules. The ignition timing varies depending upon the engine speed with this
system.
The Digital Spark Advance Module (DSAM) which was previously known as Smart Spark™ (See Figure 7-9).
This system uses a digital microprocessor that triggers the ignition modules and spark. The ignition timing
varies depending upon the engine speed with this system.
This system (Figure 7-3) consists of the following
components:
• A magnet assembly which is permanently affixed
to the flywheel.
• Two electronic capacitive-discharge ignition
modules which mount on the engine crankcase
(Figure 7-4).
• A kill switch (or key switch) which grounds the
modules to stop the engine.
• Two spark plugs.
Operation: As the flywheel rotates, the magnet
grouping passes the input coil (L1). The corresponding
magnetic field induces energy into the input coil (L1).
The resultant pulse is rectified by D1 and charges
capacitor C1. As the magnet assembly completes its
pass, it activates the triggering device (L2), which
causes the semiconductor switch (SCS) to turn on.
With the device switch "ON," the charging capacitor
(C1) is directly connected across the primary (P) of the
output transformer (T1). As the capacitor discharges,
the current initiates a fast rising flux field in the
transformer core. A high voltage pulse is generated
from this action into the secondary winding of the
transformer. This pulse is delivered to the spark plug
gap. Ionization of the gap occurs, resulting in an arc
at the plug electrodes. This spark ignites the fuel-air
mixture in the combustion chamber.