Onan CCK Service Manual

TESTING 20 AMP SYNCHRO SYSTEM
DC TEST
VALUE
Battery voltage - unit not
running
12 Volts DC
Battery voltage with unit
running at 1800 r/min or
more
14.2 -14.8
Volt DC
Resistance values {Ohms} are as follows
between wire pairs.
•BLACK
.5- .7 sl
J. 8 - 2.2*
L3- L5jy
'BLACK
■ R ED
ENGINE
RPM
USE SIMPSON 260 FOR AC VOLTAGES
RED TO
GND.
BLACK TO GND.
(Elmer Lead)
BLACK TO
BLACK
500
35 8.5
17
1000 60 15 30
2000 115 29 58
3000
160
40 80
3600 185 46 92
No Output—Stator Assembly: Examine lead wires for
loose or broken connections at the regulator and
rectifier. Use the Rxl scale on the ohmmeter for
detecting opens in the stator. Disconnect the three
wires that come from alternator stator (two black, one
red). Connect ohmmeter test leads to red Jeadwire
and ground to check continuity. The ohmmeter
reading should be approximately 2.0 ohms. See
Figure 39.
Next, connect meter to black leadwires and ground.
Approximately 0.1 ohm should be read from either
black lead to ground. If no connection exists between
ground and black leads, stator assembly should be
replaced.
Checking Rectifier Assembly: Examine each of the
two diodes for breakdown by connecting ohmmeter
{Rxl scale) from one black lead to white lead. Meter
should read 10 ohms in proper polarity. A shorted
diode would read zero resistance and would cause a
short circuit through the lead winding when in
operation. An open diode would read infinite in both
directions indicating that replacement is necessary.
See Figure 39.
Testing Regulator Assembly: To check for proper
voltage regulation, attach a DC voltmeter to battery
and operate engine at approximately 1800 rpm.
Battery voltage will climb to the preset factory setting
(14.2 to 14.8 volts).
Some Installations may vary due to voltage drop In the length of
ammeter harnesses. Other variations may stem from a loose
connector in the harness or loose or corroded battery leads. Low
voltage readings at the battery mean poor battery connections.
To test regulator, remove connector. Using the
Rxl0,000 scale of your ohmmeter, connect one meter
lead to red leadwireand other meter lead to regulator
base. No deflection should be noted on the ohmmeter
in either polarity. Next connect meter to black
ieadwire and base of regulator. Meter will defiectfu I ly
in one polarity with no deflection in the other (Figure
39).
Full Charge — Will Not Regulate: Check for broken
leads at connection to regulator plates. To be sure
regulator winding operates properly, connect red
lead to ground and start engine. A maximum of 4
amperes should be noted. This would indicate stator
winding is satisfactory. If so, replace regulator.
No Charge: If alternator does not charge when load is
applied to battery, shut off engine and disconnect one
red Ieadwire from regulator terminal. Be sure lead is
taped or isolated from conducting engine parts. Once
again, start engine. Alternator should charge to full
output; if it doesn’t, replace stator assembly.
EXTERNAL BATTERY CHARGING ALTER¬
NATOR (Optional)
This information is presented for field use only. If a
major repair should become necessary, contact your
local authorized dealer.
Brush Assembly Removal: Remove the three screws
which fasten the voltage regulator to the alternator.
Disconnect the regulator leads and remove the
regulator.
Remove the two screws on the phenolic cover and lift
out the cover and gasket See Figure 40.
Pull the brush assembly straight up and lift out.
Reverse the procedure for assembly.
Brush Assembly Tests: Connect an ohmmeter or test
lamp (12 volts) to the field terminal and to the bracket
The test lamp shouldn't light or resistance reading
should be high (infinite). If not. there is a short and the
assembly must be replaced.
Now move the one ohmmeter lead from the bracket to
the insulated brush. Use an alligator clip directly on
the brush. Be careful not to chip it. Resistance reading
should be zero (continuity).
43
Connect the ohmmeter leads to the grounded brush
and the bracket. Resistance should be zero (continui¬
ty).

Onan CCK Specifications

General

Cylinders	2
Ignition System	Battery ignition
Fuel Type	Gasoline
Cooling System	Air-cooled
Fuel System	Carburetor
Starter	Electric
Governor	Mechanical
Max RPM	1800 RPM
Engine Type	4-cycle
Bore and Stroke	3.25 x 3.625 inches (82.55 x 92.08 mm)