Kohler KT17 Service Manual

SECTION 6
ELECTRICAL SYSTEMS AND COMPONENTS
IGNITION COIL
NOTE: Erratic operation, short breaker point life,
hard starting, lack of spark, or no start, are
symptoms of coil problems which may develop.
Engines may run well for a time before any of the
symptoms are noticed.
However,
possible ignition related causes produce
similar symptoms, as do interlock systems incor-
porated on the equipment the engine powers,
which also could lead to erratic operation and
should not be overlooked.
Should any of these symptoms be encountered,
first check the following ignition related problems:
NO SPARK
1. Ignition switch off or faulty.
2. Leads disconnected or broken.
3. Spark plug bad.
4. Breaker points stuck or oxidized.
5. Condenser faulty.
POOR IGNITION
1. Spark plug gap excessive.
2. Spark plug wet or fouled.
3. Wrong spark plug.
4. Breaker points dirty.
5. Ignition timing wrong.
6. Weak condenser.
Ignition Coil Function
The ignition coil functions to transform or step up
the low voltage primary current to the high voltage
current necessary to bridge the gap between the
center and side electrodes on the spark plug.
There are two primary terminals provided on the
ignition coil and they must be connected correctly
for the coil to function properly. The positive (+)
terminal must be connected to the positive side of
the battery through the ignition switch. The break-
er points and condenser are connected to the
negative(-) terminal.
Ignition Coil Check- Terminals
Loose primary terminal nuts also can lead to
erratic operation and should be checked. Check
32
coils by removing the terminal nut and star wash-
er, and point and battery leads from primary
terminals on the coil. Check continuity across
primary terminals. If continuity is found, coil is
not faulty. If continuity is not found coil is faulty
and should be replaced.
Ignition Coil Check- Ohmmeter
NOTE: Ignition parts should be checked with the
engine stopped.
Check the continuity of the primary winding by
connecting an ohmmeter between the ( +) and (-)
terminals of the coil. The reading on the meter
when set on the Rx1 scale should be 4 - 5 ohms at
room temperature. Make sure the ohmmeter is
zeroed properly before measuring primary con-
tinuity. (See Figure 6-3).
Volt and
Ohmmeter
Coil
Figure 6-3. Continuity Check of Coil Primary
To check the secondary resistance, set ohmmeter
on Rx 100 scale, zero the meter, and connect one
test lead to each high tension terminal. The read-
ing here should be between 9,500 and 11,500 Ohms
on a good coil. If not within these limits, the
secondary is faulty and the coil should be replaced.
Note that a coil could pass these tests and still be
breaking down under operating conditions. (See
Figure 6-4.)

Kohler KT17 Specifications

General

Cooling System	Air-cooled
Type	Horizontal shaft
Horsepower	17 hp
Fuel Type	Gasoline
Displacement	0.694 liters (694 cc)
Power	17 HP (12.7 kW) @ 3600 RPM
Ignition System	Magneto
Oil Capacity	1.9 L (2.0 US qt)
Starter	Electric
Bore x Stroke	3.03 x 2.95 inches (77 mm x 75 mm)