Electrical System Test for Spark NOTE: If 2 testers are available, testing can be performed simultaneously for both cylinders. However, if only 1 tester is available, 2 individual tests must be performed. Side not being tested must have spark plug lead connected or grounded. Do not crank engine or perform tests with 1 spark plug lead disconnected and not grounded, or permanent system damage may occur. 1. With engine stopped, disconnect 1 spark plug lead. Connect spark plug lead to post terminal of spark tester and attach tester clip to a good engine ground. 2. Crank engine over, establishing a minimum of 550-600 RPM, and observe tester(s) for spark. 3.
Repeat spark test on opposite cylinder if cylinders are being tested individually. Condition Possible Cause Conclusion BATTERY CHARGING SYSTEM NOTE: Observe following guidelines to avoid damage to electrical system and components: ● Make sure battery polarity is correct. A negative (-) ground system is used. ● Disconnect rectifi er-regulator plug and/or wiring harness plug before doing any electric welding on equipment powered by engine. Disconnect all other electrical accessories in common ground with engine. ● Prevent stator (AC) leads from touching or shorting while engine is running. This could damage stator. NOTE:
20 amp charging systems use a 15 amp stator with a 25 amp rectifi er-regulator. Most engines are equipped with a 15, 20, or 25 amp regulated charging system. 15/20/25 Amp Regulated Charging System Stator Stator is mounted on crankcase behind fl ywheel. Follow procedures in Disassembly and Reassembly if stator replacement is necessary. Rectifi er-Regulator NOTE: When installing rectifi er-regulator, take note of terminal positions and install plug correctly. NOTE: Disconnect all electrical connections attached to rectifi er-regulator. Testing may be performed with rectifi er-regulator mounted or loose. Repeat applicable test procedure 2 or 3 times to determine condition of part.
Rectifi er-regulator is mounted on backing shroud assembly. To replace it, disconnect plug, remove mounting screws, and ground lead. Testing rectifi er-regulator may be performed as follows, using appropriate rectifi er-regulator tester. To test 20/25 amp rectifi er-regulators: 1. Connect single lead adapter in between B+ (center) terminal of rectifi er-regulator being tested and squared single end of tandem adapter lead. 2. Connect tester ground lead (with spring clamp) to body of rectifi er-regulator. 3. Connect red lead and 1 black lead to terminals on open end of tandem adapter lead (connections are not location specifi c). 4.
Connect remaining black lead from tester to 1 outer AC terminal on rectifi er-regulator. 5. Plug tester into proper AC outlet/power for tester being used. Turn on power switch. POWER light should be illuminated and 1 of 4 status lights may be on as well. This does not represent condition of part. 6. Press TEST button until a click is heard and then release. Momentarily 1 of 4 lights will illuminate indicating partial condition of part. To test 15 amp rectifi er-regulators: 1. Connect tester ground lead (with spring clamp) to body of rectifi er-regulator being tested. 2. Connect tester red lead to B+ terminal of rectifi er- regulator and 2 black tester leads to 2 AC terminals. 3.
Plug tester into proper AC outlet/power for tester being used. Turn on power switch. POWER light should be illuminated and 1 of 4 status lights may be on as well. This does not represent condition of part. 4. Press TEST button until a click is heard and then release. Momentarily 1 of 4 status lights will illuminate indicating condition of part. 32 KohlerEngines.com 66 690 01 Rev. C Both cylinders have good spark but engine runs poorly or existing plug condition is questionable. Spark Plug(s) Install new spark plug(s) and retest engine performance. 1 cylinder has good spark and other cylinder has no or intermittent spark. Ignition Test ignition modules and connections.
No spark at either cylinder. Ignition Switch Recheck position of ignition switch and shorted kill lead.