Guardian 4270 Diagnostic Repair Manual page 52

Section 7
DIAGNOSTIC TESTS
Figure 7-16. – Clamp-On Ammeter
TACHOMETER:
A tachometer is available from your Generac Power
Systems source of supply. Order as P/N 042223. The
tachometer measures from 800 to 50,000 RPM (see
Figure 7-17).
Figure 7-17. – Tachometer
2"
3.5"
1.75
2"
15"
Figure 7-18. – Test Bracket
Page 50
3.5"
4"
1.5"
3"
TEST BRACKET:
A starter motor test bracket may be made as shown
in Figure 7-18.
REMOVE STARTER MOTOR:
It is recommended that the Starter Motor be removed
from the engine when testing Starter Motor perfor-
mance. Assemble starter to test bracket and clamp
test bracket in vise (Figure 7-19).
TESTING STARTER MOTOR:
1. A fully charged 12 VDC battery is required.
2. Connect jumper cables and clamp-on ammeter as shown in
Figure 7-19.
3. With the Starter Motor activated (jump the terminal on the
Starter Contactor to battery voltage), note the reading on the
clamp-on ammeter and on the tachometer (rpm).
Note: Take the reading after the ammeter
and tachometer are stabilized, approximately
2-4 seconds.
4. A starter motor in good condition will be within the following
specifications:
Minimum rpm
Maximum Amps
Note: Nominal amp draw of starter in generator is
60 amps.
STARTER
CONTACTOR
STARTER
MOTOR
TACHOMETER
VISE
Figure 7-19. – Testing Starter Motor Performance
4500
50
CLAMP ON
AMP METER
12 VOLT
BATTERY