Name: Kohler 48RCLB Generator Set
Brand: Kohler

Service parts for the 48RCLB

Grouped by system, with how many of each the parts manual calls for.

Air intake

1 required

KOH-48RCLB-AIRFAir filtersee priceAmazon

Fuel system

1 required

KOH-48RCLB-FUELFuel filtersee priceAmazon

Oil system

2 required

KOH-48RCLB-OILFOil filtersee priceAmazon

KOH-48RCLB-OILOilsee priceAmazon

Belts

1 required

KOH-48RCLB-BELTBeltsee priceAmazon

Cooling system

2 required

KOH-48RCLB-COOLANTCoolantfind

KOH-48RCLB-COOLCoolant filtersee priceAmazon

Electrical

1 required

KOH-48RCLB-BATTERYBatteryfind

Ignition

1 required

KOH-48RCLB-SPARKSpark plugfind

Prices captured from merchant listings; some links are affiliate links. Confirm against your serial number before ordering.

Specifications

Fuel	Natural Gas or LP
Frequency	60.0 Hz
Standby power	48 kW
Standby kVA	48
Emissions	EPA NSPS
Controller	RDC2
Oil capacity	4.7 L
Alternator	4Q7BX (4 leads, 120/240 VAC); 4P7BX (12 leads, reconnectable)
Voltage options	120/240 V
Phase	3
Rated current	167 A
Power factor	0.8
Battery group	24
Battery cranking	630 CCA
Battery voltage	12 V
Battery quantity	1
Coolant capacity	21.3 L
Max ambient	45 °C
Dimensions (L×W×H)	2280×836×1182 mm
Dry weight	767 kg
Wet weight	767 kg
Sound level	61.0 dBA @ 7 m

Engine

Kohler KG6208

Oil capacity	6.2 L
Coolant capacity	21.3 L
Displacement	6.2 L
Aspiration	Natural
Rated speed	1800 rpm

Maintenance & consumables

for the Kohler KG6208

Item	Spec	Capacity	Part #	Interval
Air filter	Kohler 48RCLB Air Filter		KOH-48RCLB-AIRF	500 hr	Amazon eBay
Fuel filter	Kohler 48RCLB Fuel Filter		KOH-48RCLB-FUEL		Amazon eBay
Oil filter	Kohler 48RCLB Oil Filter		KOH-48RCLB-OILF	100 hr	Amazon eBay
Battery	Kohler 48RCLB Battery		KOH-48RCLB-BATTERY	1000 hr	buy
Belt	Kohler 48RCLB Belt		KOH-48RCLB-BELT	1000 hr	Amazon eBay
Coolant	Kohler 48RCLB Coolant	12.5 L	KOH-48RCLB-COOLANT	1000 hr	buy
Coolant filter	Kohler 48RCLB Coolant Filter		KOH-48RCLB-COOL	1000 hr	Amazon eBay
Fuel	Kohler 48RCLB Fuel	120.0 L	—	1000 hr
Oil	Coolant Capacity, L (gal.)	21.9 L	KOH-48RCLB-OIL	500 hr	Amazon eBay
Spark plug	Kohler 48RCLB Spark Plug		KOH-48RCLB-SPARK	1000 hr	buy

Service intervals

Item	Action	Hours	Months	Notes
Coolant system hoses and clamps	Check	10 hr		Section 3.7.2 states check every 10 hours of operation
Main tank supply level (LPG only)	Check	10 hr		Weekly or every 10 hours
Wiring and electrical connections	Check	10 hr		Section 3.6.4 states check after every 10 hours of operation
Battery voltage	Check	20 hr	3 mo	Quarterly or every 20 hours; charge or replace as needed
Fuel lines and connections	Check	20 hr	3 mo	Quarterly or every 20 hours
Battery	Inspect	120 hr	12 mo	Yearly or every 120 hours; check for cracks and corrosion
Battery cables	Clean	120 hr	12 mo	Yearly or every 120 hours
Battery fluid level	Check	120 hr	12 mo	Yearly or every 120 hours
Drive belt	Check	120 hr	12 mo	Yearly or every 120 hours; cracks, breaks, or splitting
Air cleaner element	Check	150 hr	12 mo	Yearly or 150 hours; more frequently under dusty conditions
Crankcase breather hose	Inspect	150 hr	12 mo	Yearly or every 150 hours
Engine oil and filter	Change	150 hr	12 mo	Yearly or every 150 hours
Engine oil and oil filter	Change	150 hr	12 mo	Yearly or 150 hours
Spark plugs	Check	150 hr	12 mo	Yearly or every 150 hours
Air cleaner element	Change	400 hr	36 mo	3 years or every 400 hours; see equipment operation manual
Air cleaner element	Replace	400 hr	12 mo	Yearly or 400 hours; more frequently under dusty conditions
Air induction (air-fuel mixer, throttle body, DEPR, intake elbow, intake manifold)	Check	500 hr	36 mo	3 years or every 500 hours; check for leaks
Engine air induction system	Check	500 hr	36 mo	3 years or 500 hours; check for leaks
Engine air induction system leaks	Check	500 hr	36 mo	3 Years or 500 hours
Engine coolant	Change	500 hr	36 mo	3 years or every 500 hours; with long-life coolant the interval is 5000 hours or 5 years
Hoses	Check	500 hr	36 mo	3 years or every 500 hours; replace as needed
Ignition coil wires	Check	500 hr	36 mo	3 years or every 500 hours; replace as needed
Intake manifold	Check	500 hr	36 mo	3 years or every 500 hours; vacuum leaks
Spark plug and electrode gap	Adjust	500 hr	36 mo	3 years or every 500 hours; adjust gap if necessary, replace if discolored or damaged
Spark plug gap	Adjust	500 hr	36 mo	3 years or 500 hours; replace spark plugs if discolored or damaged
Spark plug wires	Check	500 hr	36 mo	3 years or every 500 hours; replace if cut, abraded, or hardened
Spark plug wires	Replace	500 hr	36 mo	3 years or 500 hours; check for cuts, hardening or abrasions and replace as needed
Winding resistance readings	Test	500 hr	36 mo	3 years or 500 hours; measure with insulation tester (Megger) with SCR assembly or rectifier and load leads disconnected; have this service performed by an authorized distributor or dealer
Wire-cable insulation	Check	500 hr	36 mo	3 years or 500 hours
Wire-cable insulation condition	Check	500 hr	36 mo	3 Years or 500 hours
Distributor cap and rotor	Change	2000 hr	60 mo	5 years or every 2000 hours
Engine maintenance requirements	Other	2000 hr	60 mo	5 years or 2000 hours; see the Engine Operation Manual
Exhaust manifold	Check	2000 hr	60 mo	5 years or every 2000 hours; replace as needed
Exhaust piping	Check	2000 hr	60 mo	5 years or every 2000 hours; check for leaks
Fuel shutoff valve	Check	2000 hr	60 mo	5 years or every 2000 hours; operation
HEGO (oxygen) sensor connections and wires	Check	2000 hr	60 mo	5 years or every 2000 hours
Spark plug wires	Change	2000 hr	60 mo	5 years or every 2000 hours
Vacuum lines and fittings	Inspect	2000 hr	60 mo	5 years or every 2000 hours; cracks, breaks, or splitting; replace as needed
Wiring	Inspect	2000 hr	60 mo	5 years or every 2000 hours; cuts, abrasions, or corrosion
Battery and rack corrosion	Clean		12 mo	Yearly; remove corrosion, clean and dry

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Service specifications

Type	Item	Value	Unit	Condition
Gap	Spark plug gap	0.03	in.
Gap	Spark plug gap	0.76	mm (0.03 in.)
Gap	Spark plug gap	0.9	mm
Other	Air–Fuel Mixer	Tamper-proof; nonadjustable
Other	Allowable water vapor (NG)	112.3	kg per 1 million m3	less than
Other	Alternator rated current	130	A
Other	Battery cell specific gravity difference (maximum)	0.01
Other	Battery specific gravity, fully charged	1.260		at 80 F (26.7 C)
Other	Battery specific gravity, needs charging (below)	1.215		at 80 F (26.7 C)
Other	Battery wrap length	1067 (42)	mm (in.)
Other	Battery wrap length	864 (34)	mm (in.)
Other	Compression ratio	10.5:1
Other	Cylinder fire order	1-8-4-3-6-5-7-2
Other	Direct Acting Electronic Pressure Regulator (DEPR)	Nonadjustable
Other	Electric starter	1.2	kW
Other	Fuel handling and supply component constraints	UL 2200: Standard for Stationary Engine Equipment Assemblies
Other	Heater wrap rating	50	Watts
Other	Heater wrap rating	65	Watts
Other	LPG fuel type	HD-5 or HD-10
Other	NG approximate supply volume	37.257	kJ/m3	1000 BTU/ft.3
Other	Natural gas minimum flow	1504	ft3/hr	@ 6.0” W.C.
Other	Natural gas minimum flow	42.6	m3/hr	@ 6.0” W.C.
Other	Plug cord length	75 (3)	mm (in.)
Other	Power cord length	1677 (66)	mm (in.)
Other	Power cord length	1830 (72)	mm (in.)
Other	Power cord length	483 (19)	mm (in.)
Other	Rated output @ 1800 rpm	100.6	hp	NG
Other	Rated output @ 1800 rpm	103.3	hp	LPG
Other	Rated output @ 1800 rpm	75.0	kW	NG
Other	Rated output @ 1800 rpm	77.0	kW	LPG
Other	Throttle	Nonadjustable, ECM controlled
Other	Voltage regulator gain (outer loop) adjustment range	1--255		default 16
Other	Voltage regulator volts/Hz cut-in frequency	42--62	Hz	default 59
Other	Voltage regulator volts/Hz slope	1--10	%	default 4
Pressure	Fuel supply pressure, LPG	1.2--2.7	kPa (5--11 inches H2O)	generator running at rated load
Pressure	Fuel supply pressure, NG	1.7--2.7	kPa (7--11 inches H2O)	generator running at rated load
Pressure	LPG maximum fuel pressure (engine OFF, no load)	11.0	in. W.C.	engine OFF, no load
Pressure	LPG minimum fuel pressure (engine ON, full load)	5.0	in. W.C.	engine ON, full load
Pressure	NG maximum fuel pressure (engine OFF, no load)	11.0	in. W.C.	engine OFF, no load
Pressure	NG minimum fuel pressure (engine ON, full load)	7.0	in. W.C.	engine ON, full load
Pressure	Pressure cap rating	83--110	kPa (12--16 psi)
Pressure	Pressure cap rating	83-110	kPa (12-16 psi)
Pressure	Radiator pressure cap rating	83--110	kPa
Pressure	Secondary fuel regulator maximum inlet pressure	2.7	kPa (6 oz./in.2) or 280 mm (11 in.) water column
Resistance	Engine compartment temperature sensor resistance at 100_C (212_F)	180--200	Ohms	100_C (212_F)
Resistance	Engine compartment temperature sensor resistance at 30_C (86_F)	2100--2400	Ohms	30_C (86_F)
Speed	Engine crank disconnect speed	750	RPM
Speed	Engine idle speed (default)	1350	RPM
Speed	Engine run speed (50 Hz)	1500	RPM	50 Hz
Speed	Engine run speed (60 Hz)	1800	RPM	60 Hz
Speed	Normal running speed (engine metering display)	1800	RPM
Temperature	Block heater thermostat cut-off temperature	27--38	°C	coolant temperature
Temperature	Block heater thermostat cut-off temperature	80--100	°F	coolant temperature
Temperature	Coolant fan high-speed threshold	93	_C (200_F)	coolant temperature
Temperature	Coolant fan low-speed threshold	79	_C (175_F)	coolant temperature
Temperature	Coolant freezing protection (50% ethylene glycol)	-37	C
Temperature	Coolant overheating protection (50% ethylene glycol)	129	C
Temperature	Engine compartment fan high-speed threshold	57	_C (135_F)	engine compartment temperature
Temperature	Engine compartment fan low-speed threshold	46	_C (115_F)	engine compartment temperature
Temperature	Engine compartment temperature shutdown threshold	79	_C (174_F)

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Recommended fluids

Fluid	Grade	Standard	Ambient	Capacity	Notes
Coolant	50% ethylene glycol			0.6 L	Provides freezing protection to --37_C (--34_F) and overheating protection to 129_C (265_F). Do not use alcohol or methanol antifreeze. Coolant added after block heater installation is approximately 0.6 L (0.2 gal).
Coolant	50% ethylene glycol and 50% clean, softened water			21.3 L	Provides freezing protection to -37_C (-34_F) and overheating protection to 129_C (265_F). Do not use alcohol or methanol antifreeze. Do not use less than 50% or more than 50% ethylene glycol. 21.9 L (5.8 gal.) with block heater.
Coolant	50% ethylene glycol-based long-life coolant / 50% clean, softened water		-37°C to 129°C	20.8 L	48RCLB; freeze protection to -37C (-34F), overheat protection to 129C (265F)
Coolant	50% ethylene glycol-based long-life coolant and 50% clean, softened water		-37°C to 129°C	20.8 L	Capacity 20.8 L (5.5 gal.); with block heater 21.4 L (5.7 gal.). Do not mix long-life and conventional coolants. Do not use alcohol or methanol antifreeze. When long-life coolant is used, change interval is 5000 hours or 5 years.
Coolant	50% long life coolant and 50% clean, softened water		above -37°C		Solution provides freezing protection to –37°C (–34°F) and overheating protection to 149°C (300°F). Do not mix long life and conventional coolants.
Coolant	Ethylene glycol-based long-life coolant		-37°C to 129°C	20.8 L	50% coolant/50% water mix; 5.5 gal.; with block heater 21.4 L (5.7 gal.); -37C (-34F) freeze protection, 129C (265F) boil protection at 50% mix
Engine oil	Rotella T4 SAE 15W40 or equivalent	Zinc 1000-1200 ppm; Phosphorous 1000-1200 ppm; Sulfate Ash Content 1.0% or lower		6.2 L	Oil dry fill capacity 6.2 L (6 qt.). Do not mix different brands or types of oil. Do not overfill or underfill.
Engine oil	SAE 10W-40	KOHLER Genuine Oil; zinc 1000--1200 ppm; phosphorous 1000--1200 ppm; sulfated ash 1% or lower		4.7 L	Fully synthetic, engineered for gaseous-fueled (NG/LPG) engines; capacity 4.7 L (5.0 qt.) for 48RCLB and 60RCLA
Engine oil	SAE 15W-40	Rotella T4 or equivalent (zinc 1000-1200 ppm, phosphorous 1000-1200 ppm, sulfated ash ≤1.0%)		4.7 L	5.0 qt.
Fuel	Natural Gas or LP Gas vapor withdrawal				Fuel supply line inlet 1 in. NPT; natural gas fuel supply pressure 1.24-2.74 kPa (7-11 in. H2O); LPG vapor withdrawal fuel supply pressure 1.24-2.74 kPa (5-11 in. H2O)
Fuel	LPG: HD-5 or HD-10; NG: standard pipeline	NG approximate supply volume 37.257 kJ/m3 (1000 BTU/ft.3)	0°C to 45°C		Operating temperature range 0°C (32°F) to 45°C (113°F) unaided. NG minimum flow 42.6 m3/hr (1504 ft3/hr) @ 6.0” W.C.

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Fault codes

Code	Name	Meaning	Severity	Action
AC Sens Loss Shutdwn	Loss of AC sensing shutdown	Less than 5% of rated voltage measured on Phase A (or B or C if 3 phase) for 3 seconds, only in AUTO, only after acceptable voltage (> 5% of UV setting) has been detected.	Shutdown	Check for loose wiring and connections. Check all AC leads. Troubleshoot alternator.
AC Sens Loss Warning	Loss of AC sensing warning	Less than 5% of rated voltage measured on Phase A (or B or C on 3 phase), for 1 second, 10 seconds after crank disconnect.	Warning	Check for loose wiring and connections. Check all AC leads. Troubleshoot alternator.
AC Sens Lost	AC Sensing Lost	In Auto mode, generator output AC sensing is lost; starts 10 seconds after crank disconnect. Warning after 1 sec if no output detected; shutdown after 3 sec if voltage was present then lost.	Warning	Contact an authorized distributor/dealer for service.
ATS Com Error	ATS Communication Error	Warning is displayed if RXT interface connection is lost.	Warning	Check communication wiring between transfer switch interface board and generator set.
ATS ComError Warning	ATS communication error	The controller has lost communications with the RXT ATS that had previously been communicating properly.	Warning	Check connection to ATS module.
ATS Fail Xfr Warning	ATS fail to transfer	The RXT ATS has reported a fail to transfer; the digital output for ATS Fail To Transfer (PIM) is active.	Warning	Consult ATS manual for troubleshooting.
ATS PhaseRot	ATS Phase Rotation Mismatch	Transfer switch phase rotation does not match; ATS will not transfer.	Warning	Correct the ATS connection. Refer to the ATS Installation manual, wiring diagrams, and labels on the transfer switch.
ATS PhaseRot Warning	ATS phase rotation	The RXT ATS has reported a Phase Rotation Mismatch (3 phase only) and the ATS will not transfer.	Warning	Check wiring to ATS. Consult ATS manual.
Accy PwrOver	Accessory Power Overload	An over current fault (short circuit) on the accessory controller power output.	Warning	Contact an authorized distributor/dealer for service.
Accy PwrOver Warning	Accessory Power Overload	An over current fault (short circuit) on the accessory controller power output.	Warning	Contact an authorized distributor/dealer for service
Alt Protect Shtdwn	Alternator Protection Shutdown	High generator current has been detected. The generator set shuts down to protect the alternator from damage caused by overheating the windings.	Shutdown	Reduce the load.
Aux Input	Auxiliary Input	An optional customer-connected input is closed. (Digital input from optional PIM.)	Shutdown	Check customer-supplied equipment.
Aux Input Shutdwn	Auxiliary input shutdown	The digital input for a custom shutdown (AuxiliaryInputShutdown - PIM) was activated (low).	Shutdown	Check customer equipment connected to the PIM module.
Aux Input Warning	Auxiliary input warning	The digital input for a custom warning (AuxiliaryInputWarning - PIM) is active (low).	Warning	Check customer equipment connected to the PIM module.
Batt Chg Flt	Battery Charger Fault	Input to PIM from an external battery charger (not the built-in charger).	Warning	Check external battery charger.
Batt Chg Flt Warning	Battery charger fault warning	The digital input for Battery Charger Fault Warning (PIM) is active (low). For an external battery charger only.	Warning	Check customer equipment connected to the PIM module.
Battery High Warning	Battery high warning	Battery voltage above the high warning setting for 10 seconds or more.	Warning	Check cranking battery.
Battery Low Shutdwn	Battery low shutdown	Battery voltage dropped to 11 VDC or less for 30 seconds or more, after running at least one minute.	Shutdown	Check cranking battery. Check battery charger DC output voltage from RDC2 on lead CHO to the battery.
Battery Low Warning	Battery low warning	Battery voltage below the low warning setting for 90 seconds or more; checked before allowing an exercise to start.	Warning	Check cranking battery. Check battery charger DC output voltage from RDC2 on lead CHO to the battery.
Battery Voltage High	Battery Voltage High	Engine starting battery voltage rises above 125% of the battery voltage setting for more than 10 seconds. Inhibited during the engine crank cycle. Clears when the battery voltage returns to an acceptable level.	Warning	Check the battery rating/condition and the battery charger operation
Battery Voltage Low	Battery Voltage Low	Engine starting battery voltage falls below the battery voltage setting (typically 12.5 volts) for more than 90 seconds when the engine is not running. Inhibited during the engine crank cycle.	Warning	Check the battery rating and condition. Check the battery charger operation. Charge or replace the battery.
CAN Shutdown	CAN shutdown	The ECM shut down the engine and reported an unknown fault code.	Shutdown	Troubleshoot engine operation per the engine service manual.
CAN comm fault	Engine CAN Communications Fault	Engine CAN communications fault.	Shutdown	Check wiring to ECM; check power to ECM
Chk DateTime Warning	Check date and time warning	DC power to the controller has been interrupted and the date and time may not be correct.	Warning	Verify the time and date settings.
Compartmnt Temp Shutdwn	Compartment temperature shutdown	Engine compartment air temperature has exceeded 174_F (79_C).	Shutdown	Troubleshoot fan circuit failure and/or temperature sensor circuit. Check for blockage of intake or exhaust vents.
Compartmnt Temp Warning	Compartment temperature warning	Engine compartment temperature above 167_F (75_C).	Warning	Troubleshoot fan circuit failure and/or temperature sensor circuit. Check for blockage of intake or exhaust vents.
Coolant Level Low Shutdwn	Coolant level low shutdown	The coolant level sensor indicated low coolant for 5 seconds or more.	Shutdown	Check coolant level and fill as needed. Check for air in cooling system. Check the coolant level sensor operation.
Coolant Temp High Shutdwn	Coolant temperature high shutdown	The ECM shutdown the engine and reported high coolant temperature as the fault.	Shutdown	Check engine cooling system. Check radiator fans for proper operation. Check for blockage of inlet and exhaust vents.
Coolant Temp High Warning	Coolant temperature high warning	The ECM is reporting high coolant temperature.	Warning	Check engine cooling system. Check radiator fans. Check for blockage of vents.
Coolant Temp Low Warning	Coolant temperature low warning	The ECM is reporting low coolant temperature.	Warning	Check cooling system.
Coolant Temp No Sig Shutdwn	Coolant temperature no signal shutdown	The ECM shutdown the engine and reported no coolant temperature signal as the fault.	Shutdown	Check cooling system and coolant level sensor circuit.
Default Pars Warning	Default Parameters	The controller has been loaded with default parameters.	Warning	Configure settings as needed for desired operation.
ECM Addr Err Shutdwn	ECM address error shutdown	There is a conflict in addressing on the ECM CAN bus.	Shutdown	Verify no other devices connected and broadcasting on the CAN bus.
ECM Comm Err Shutdwn	ECM communication error shutdown	Communication with the ECM was lost for 4 or more seconds.	Shutdown	Check CAN communication wiring between controller and ECM.
ECM Mismatch Shutdwn	ECM mismatch shutdown	The ECM does not match any of the supported models.	Shutdown	Verify controller configuration using SiteTech. Consult local service technician.
Emerg Stop Shutdwn	Emergency stop shutdown	The emergency stop circuit was tripped (open circuit).	Shutdown	Check E-stop circuit for open switches, broken wires, disconnected wires, etc.
Engine Coolant Temperature High	Engine Coolant Temperature High	Engine coolant temperature exceeds the maximum temperature for more than 5 seconds. Function becomes active after crank disconnect.	Shutdown	Check for blocked air inlets and exhaust outlets.
Engine Oil Pressure Low	Engine Oil Pressure Low	The engine ECM indicates low oil pressure for more than 5 seconds. Function becomes active 30 seconds after crank disconnect. Does not protect against low oil level.	Shutdown	Check for leaks in the lubrication system. Check the oil level and add oil if the level is low.
Engine Speed High Shutdwn	Engine speed high shutdown	Engine speed, as calculated from AC frequency, was above the high speed setting for 0.3 seconds or more; or the ECM reported overspeed.	Shutdown	Troubleshoot engine operation per the engine service manual.
Engine Speed Low Shutdwn	Engine speed low shutdown	After crank disconnect, engine speed was below the low speed setting for 3 seconds or more.	Shutdown	Troubleshoot engine operation per the engine service manual.
EngineSpeed High	Engine Speed High	Engine speed exceeds 115% of the normal running speed for more than 0.3 seconds.	Shutdown	Contact an authorized distributor/dealer for service.
EngineSpeed Low	Engine Speed Low	Engine speed drops below 85% of the normal running speed for more than 3 seconds.	Shutdown	Reduce the load; contact an authorized distributor/dealer for service
Exer Not Sch	Exercise Not Scheduled	No exercise has been scheduled on the RDC2 controller.	Warning	See Section 2.5 for instructions to set the exerciser.
Exer Not Sch Warning	Exercise not scheduled warning	There is no exercise scheduled.	Warning	Set the exercise schedule.
Frequency High Shutdwn	Frequency high shutdown	Frequency measured on Phase A exceeded the high frequency setting for 10 seconds, 10 seconds or more after crank disconnect.	Shutdown	Troubleshoot engine operation per the engine service manual.
Frequency Low Shutdwn	Frequency low shutdown	Frequency measured on Phase A was less than the low limit for 10 seconds, or 10 Hz or more below rated for 60 seconds or more, 10 seconds or more after crank disconnect.	Shutdown	Troubleshoot engine operation per the engine service manual.
Fuel Leak Shutdwn	Fuel leak shutdown	The digital input for Fuel Tank Leak Shutdown (PIM) was activated (low).	Shutdown	Check customer equipment connected to the PIM module.
Fuel Leak Warning	Fuel leak warning	The digital input for Fuel Tank Leak Warning (PIM) is active (low).	Warning	Check customer equipment connected to the PIM module.
Fuel Level Low Shutdwn	Fuel level low shutdown	The digital input for Low Fuel Level Shutdown (PIM) was activated (low).	Shutdown	Check customer equipment connected to the PIM module.
GenBrkerOpen Warning	Generator Circuit Breaker Open	There is voltage at the generator set but no voltage measured on the emergency side of the ATS (Model RXT transfer switch).	Warning	Check line circuit breaker. Check for and correct short circuits or overloading on the load side before resetting the circuit breaker.
Generator Frequency High	Generator Frequency High	Governed frequency exceeds 110% of the system frequency setpoint for more than 10 seconds. Function becomes active 10 seconds after engine start.	Shutdown	Contact an authorized distributor/dealer for service.
Generator Frequency Low	Generator Frequency Low	Governed frequency falls below 90% of the system frequency setting for more than 10 seconds, or 1 Hz below the system frequency setting for more than 60 seconds. Function becomes active 10 seconds after engine start.	Shutdown	Reduce the load and restart; contact an authorized distributor/dealer for service
Generator Voltage L1-L2 High	Generator Voltage High	Output voltage exceeds 120% of the system nominal voltage for more than 2 seconds.	Shutdown	Contact an authorized distributor/dealer for service.
Generator Voltage L1-L2 Low	Generator Voltage Low	Output voltage falls below 80% of the nominal system voltage for more than 10 seconds.	Shutdown	Reduce the load and restart the generator set. Contact an authorized distributor/dealer for service.
Generator VoltageL1-L2 High	Generator Voltage High	Output voltage exceeds 120% of the system nominal voltage for more than 2 seconds.	Shutdown	Contact an authorized distributor/dealer for service
Generator VoltageL1-L2 Low	Generator Voltage Low	Output voltage falls below 80% of the nominal system voltage for more than 10 seconds.	Shutdown	Reduce the load and restart; contact an authorized distributor/dealer for service
Ground Fault Warning	Ground fault warning	The digital input for Ground Fault Warning (PIM) is active (low).	Warning	Check customer equipment connected to the PIM module.
Lo Crank Vlt	Low Cranking Voltage	Battery voltage falls below 60% of system battery voltage for more than 6 seconds while the starter is engaged.	Warning	Charge or replace the battery.
Lo Crank Vlt Warning	Low cranking voltage warning	During cranking, battery voltage less than 60% (7.2V or 14.4V) for 6 seconds or more during cranking.	Warning	Check cranking battery.
Locked Rotor	Locked Rotor	No engine rotation sensed during cranking; shuts down 3 seconds after fault detected.	Shutdown	Check the battery; check for loose connections; contact an authorized distributor/dealer for service
Locked Rotor Shutdwn	Locked rotor shutdown	No rotation of the engine or alternator was detected for 3 seconds or more during cranking.	Shutdown	Check cranking circuit. Troubleshoot the engine. Check alternator connections to controller and auxiliary winding circuit breaker. Troubleshoot the alternator.
MainPwrOverL Shutdown	Main Power Overload Shutdown	Over current fault on the controller power output (short circuit).	Shutdown	Contact an authorized distributor/dealer for service.
MainPwrOverL Shutdwn	Main power overload shutdown	The internal current limit circuit has tripped, indicating an overcurrent condition on the DC power supply circuit.	Shutdown	Check crank, run, and flash relay circuits for short circuits.
Not In Auto Warning	Not in auto warning	The RDC2 controller is not in AUTO; the generator will not start from an ATS or remote device.	Warning	Press the Auto button to ensure automatic system operation.
Not in Auto	Not in Auto	The generator set is not in Automatic (standby) mode. Remote start and stop commands from a transfer switch or remote switch will be ignored.	Warning	Press AUTO to place the generator set in Automatic mode, when appropriate.
OB1 CommLoss	Option board 1 communication loss	Communications with option board #1 (PIM, load management device, or RXT) has been lost.	Warning	Check RBUS wiring to inoperative option board.
OB2 CommLoss	Option board 2 communication loss	Communications with option board #2 has been lost.	Warning	Check RBUS wiring to inoperative option board.
OB3 CommLoss	Option board 3 communication loss	Communications with option board #3 has been lost.	Warning	Check RBUS wiring to inoperative option board.
OB4 CommLoss	Option board 4 communication loss	Communications with option board #4 has been lost.	Warning	Check RBUS wiring to inoperative option board.
Oil Pressure Low Shutdwn	Oil pressure low shutdown	The ECM shutdown the engine and reported low oil pressure as the fault.	Shutdown	Check for oil leaks. Check the oil level and add oil if low. Check the oil pressure sensor.
Oil Pressure Low Warning	Oil pressure low warning	The ECM is reporting a low oil pressure warning.	Warning	Check the oil level and add oil if low. Check the oil pressure sensor.
Oil Pressure No Sig Shutdwn	Oil pressure no signal shutdown	The ECM shutdown the engine and reported no oil pressure signal as the fault.	Shutdown	Check engine oil pressure sensor and wiring to the ECM. Troubleshoot engine.
Over Crank	Over Crank	Three unsuccessful starting attempts.	Shutdown	Check the fuel supply, spark plug, and battery; check for loose connections; contact an authorized distributor/dealer for service
Over Crank Shutdwn	Overcrank shutdown	The engine was not successfully started after the completion of the last crank cycle plus the 15 second delay.	Shutdown	Check fuel supply. Check cranking circuit. Check cranking battery. Troubleshoot engine.
RBUS ComError Warning	RBUS communication error warning	The controller has lost communications with a PIM or load management device that had previously been communicating properly.	Warning	Check connection to the PIM or load management device.
Spd Sens Flt Shutdwn	Speed sensor fault shutdown	The controller, or the ECM, shutdown the generator because the speed signal was lost.	Shutdown	Check speed sensor and circuitry to ECM.
Speed Sensor Fault	Speed Sensor Fault	Engine speed sensor has failed or engine stalled.	Shutdown	Contact an authorized distributor/dealer for service.
Total Power High ShtDwn	Total Power High Shutdown	Measured load is greater than 102% of the generator set power rating for more than 1 minute.	Shutdown	Reduce the load.
Volts L1-L2 High Shutdwn	Volts L1-L2 high shutdown	Voltage measured from Phase A to Phase B exceeded the high limit for a time greater than the delay setting (default 2 seconds).	Shutdown	Troubleshoot alternator; see alternator service manual.
Volts L1-L2 Low Shutdwn	Volts L1-L2 low shutdown	Voltage measured from Phase A to Phase B was greater than 5% of rated but less than the low voltage setting for a time greater than the delay setting (default 10 seconds).	Shutdown	Troubleshoot alternator; see alternator service manual.

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Procedures

Engine Speed Governor Settings adjustment

Tools: RDC2 controller keypad or SiteTech software

Adjust the Engine Speed Adjustment (range 0 to 99; default 50) from the front panel or SiteTech.
Calculate resulting speed: (System Frequency x 30) + (Setting - 50) = RPM.
Note that Engine Speed Gain Adjustment has no effect (gain controlled by engine ECM).

Procedure to Change Settings adjustment

⚠ Use caution when navigating the controller menus; in some menus pressing the Select button can enable editing of the controller settings.

Press the Select button to enter the main menu.
Press the down arrow button until the desired menu is displayed.
Press the Select button to enter the selected menu.
Press the down arrow button to step through the parameters in the selected menu.
To change a setting, press the Select button; the selected setting flashes.
Press the up or down arrow buttons to increase or decrease the setting.
When the desired setting is shown, press Select; the value stops flashing.
Repeat steps 5 through 7 for each setting on the screen.
Press the down arrow to step to the next screen.
To exit, press the down arrow button until Return is displayed and press Select.
Press the AUTO or OFF button to exit the main menu.

RDC2 Voltage Calibration Using SiteTech adjustment

Tools: digital voltmeter, personal computer, SiteTech software

Connect PC to controller via USB
With generator off, connect multimeter across L1/L2 (AC volts)
Start generator set
Compare voltmeter reading to controller display
Calculate new Genset Calibration Factor Voltage using (Vmeter / Vcontrol) x Fold = Fnew
Enter new value into SiteTech and click Apply Changes
Verify voltmeter matches controller display
Repeat for L2-L3 and L3-L1 if three-phase
Press OFF to stop generator set

RDC2 Voltage Calibration Using the Controller Keypad adjustment

Tools: digital voltmeter

With generator off, connect digital multimeter across L1 and L2, set to AC volts
Start generator set with RUN button
Navigate to Generator Metering menu, press Select; Volts L1-L2 displayed
Press Select; voltage number flashes
Use up/down arrows to match voltmeter reading
Press Select to confirm
Step to Return screen
Press OFF to stop generator set

VSC Current (Load) Calibration Using the Controller Keypad adjustment

Tools: clamp-on DC current probe or DC current meter

Connect DC current probe/clamp meter to measure generator current
Start generator with RUN button
Adjust system voltage to obtain rated current output with battery bank attached (or use load bank)
Trip output breaker
Navigate to Generator Metering menu, select Generator Load
Press and hold Select for No-Load Calibration; verify breaker open, confirm Yes
Close output breaker; verify rated output current, confirm Yes
Verify displayed load is correct; recalibrate if necessary
Press OFF to stop generator set

Voltage Calibration Using SiteTech adjustment

⚠ Testing live electrical circuits. Hazardous voltage or current will cause severe injury or death.

Tools: Digital voltmeter, Personal computer with SiteTech, USB cable

With generator off, connect a digital multimeter across L1 and L2 (AC volts).
Start the generator set by pressing RUN.
Compare the voltmeter reading to the controller-displayed voltage.
Calculate a new value: (Vmeter / Vcontrol) x Fold = Fnew.
Enter the new Genset Calibration Factor Voltage L1-L2 in SiteTech and click Apply Changes.
Wait a few seconds and re-compare voltmeter and controller readings.
Press OFF to stop the generator set.
Repeat for L2-L3 and L3-L1 if necessary (three-phase only).

Voltage Calibration using the RDC2 Controller Keypad and Menus adjustment

⚠ Testing live electrical circuits. Hazardous voltage or current will cause severe injury or death.

Tools: Digital voltmeter, RDC2 controller keypad

With generator off, connect a digital multimeter to measure output voltage across L1 and L2 (AC volts).
Start the generator set by pressing RUN.
Navigate to the Generator Metering menu.
Display Volts L1-L2 and compare with the voltmeter reading.
Press Select; the voltage flashes. Adjust with up/down arrows to match the voltmeter.
Press Select to save; wait 30 to 60 seconds for the reading to stabilize.
For three-phase models, repeat for L2-L3 and L3-L1.
Step down to Return and press Select to exit.
Press OFF to stop the generator set.

Fuel Valve Operation Test Procedure diagnostic

⚠ Explosive fuel vapors. Use extreme care when handling, storing, and using fuels.

Tools: 12 VDC power source

Disconnect the positive (+) battery lead from the gas valve terminal.
Apply 12 VDC to the gas valve terminal and listen for an audible click indicating actuation.
Repeat steps 1 and 2 on the second solenoid valve.
Replace the gas valve if either valve does not actuate in step 2.

LED Optic Board Test Procedure diagnostic

⚠ Testing the photo transistor circuit board. Hazardous voltage will cause severe injury or death. Do not expose the photo transistor board to external light.

⚠ Disconnecting the electrical load. Hazardous voltage will cause severe injury or death.

Tools: Flashlight, Voltmeter, Black electrical tape

Remove the enclosure rear panel from the generator end.
Remove the LED optic board and holder.
With the generator running at no load, shine a flashlight at the exposed photo transistor.
Observe AC output voltage; high output indicates the FRX activator board is functioning, and voltage should drop when the flashlight is removed.
If high voltage exists with the flashlight off, stop the unit and tape over the photo transistor; restart to check for external light.
With the generator running at no load, approximately 1--2 volts DC should be observed at 3B (+) and 5B (--) at the LED optic board.
Shine the flashlight; the DC voltage reading should drop.
Stop the generator set.

Procedure to Reset the Controller after a Fault Shutdown diagnostic

⚠ Always identify and correct the cause of a fault shutdown before resetting the controller.

Press the Select button to go to the Overview menu.
Press Select again; the active fault is displayed.
Press Select; Confirm Clear Fault: NO is displayed.
Press the Up arrow button; Confirm Clear Fault: YES is displayed.
Press the Select button to enter YES and clear the fault.
Press the Select button to return to the overview menu.
Press AUTO to put the generator set into automatic mode.

Temperature Sensor Test Procedure diagnostic

Tools: Ohmmeter

Press OFF to stop the generator set and allow it to cool.
Disconnect the temperature sensor and measure resistance across it with an ohmmeter; resistance varies with temperature per Figure 6-11.
If resistance is very low (short) or very high (open), replace the sensor.

12-Lead Generator Reconnection installation

⚠ Disconnect battery cables before working on the generator set, negative lead first

Tools: digital multimeter (DVM), voltmeter

Press OFF on the RDC2 controller
Disconnect engine starting battery, negative lead first
Disconnect utility power to the generator set
Verify line circuit breaker is sized correctly for new voltage/amperage; replace if necessary
Select desired voltage connection and connect leads per diagram
Reconnect engine starting battery, negative lead last
Enter the RDC2 Genset System menu; check and change system voltage, frequency, and phase settings
Connect a digital multimeter to the generator set output
Press RUN to start the generator set
Use a voltmeter to check for correct voltage output; calibrate per Section 3.5 if necessary
Press OFF to stop the generator set
Reconnect utility power
Press AUTO to place the generator set in automatic mode

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Voltage reconnection

Voltage	Phase	Connection	Leads	Notes
		LPG Configuration	Connect lead 49 to lead N17 (ground)	Change fuel type in Genset System menu on RDC2 controller
		Natural Gas Configuration	Disconnect lead 49 from N17	Change fuel type in Genset System menu on RDC2 controller
	3	Delta, Low Wye, High Wye, Dogleg	12-lead reconnectable alternator	4-lead alternators are not reconnectable. Setting system voltage above 300 VAC automatically switches the controller from low wye to high wye.
100/200	1	Single
100/200	3	Delta
110/220	1	Single
110/220	3	Delta
115/230	1	Single
120	1	Single		Genset System Voltage/Frequency/Phase table for controller setup
120/208	3	4P7BX	12, Reconnectable	Three-phase
120/208	3	Three-Phase Wye
120/208	3	Wye
120/240	1	4Q7BX	4	Single-phase
120/240	1	Single
120/240	1	Single Phase
120/240	3	4P7BX	12, Reconnectable	Three-phase
120/240	3	Delta
120/240	3	Three-Phase Delta
127/220	3	4P7BX	12, Reconnectable	Three-phase
127/220	3	Three-Phase Wye
127/220	3	Wye
220	1	Single
220/380	3	Three-Phase Wye
220/380	3	Wye
230	1	Single
230/400	3	Three-Phase Wye
230/400	3	Wye
240	1	Single
240/416	3	Three-Phase Wye
240/416	3	Wye

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Common questions

What is the power rating of the Kohler 48RCLB?

The Kohler 48RCLB is rated 48 kW standby (48.0 kVA).

Which engine powers the Kohler 48RCLB?

The Kohler 48RCLB is powered by the Kohler KG6208 engine.

What kind of fuel does the Kohler 48RCLB run on?

The Kohler 48RCLB runs on Natural Gas or LP.

What is the oil capacity of the Kohler 48RCLB?

The Kohler KG6208 engine in the Kohler 48RCLB has an oil capacity of 6.2 liters.

What alternator comes on the Kohler 48RCLB?

The Kohler 48RCLB uses a 4Q7BX (4 leads, 120/240 VAC); 4P7BX (12 leads, reconnectable) alternator.

Which oil filter part number does the Kohler 48RCLB take?

The Kohler 48RCLB uses oil filter part number KOH-48RCLB-OILF.

Which fuel filter part number does the Kohler 48RCLB take?

The Kohler 48RCLB uses fuel filter part number KOH-48RCLB-FUEL.

What air filter fits the Kohler 48RCLB?

The Kohler 48RCLB uses air filter part number KOH-48RCLB-AIRF.

Troubleshooting

Symptoms & remedies

Symptom	Cause	Remedy
The generator set does not crank.	Battery weak or dead, Battery connections reversed or poor, Blown fuse(s)	Recharge or replace the battery, Check the connections, Replace the fuse. Contact an authorized Kohler distributor/dealer for service if fuse blows repeatedly
The generator set cranks but does not start, starts hard, lacks power, or operates erratically.	Air cleaner clogged, Battery weak or dead, Battery connection poor, Spark plug wire connection loose	Clean and/or replace the air cleaner element, Recharge or replace the battery, Clean and tighten the battery connections, Check the spark plug wires
Low oil pressure shutdown.		Check for oil leaks. Check the oil level and add oil if necessary
Fuel pressure insufficient.		Check the fuel supply and valves
Engine malfunction.		Contact an authorized Kohler distributor/dealer
No AC output.	AC circuit breaker in the OFF position	Place the circuit breaker in the ON position

Fault codes and symptom→remedy steps extracted from this model’s service/owner documentation; verify against the official manual before servicing. Full Kohler 48RCLB troubleshooting guide (17 entries) →

Parts

Part #	Description	Qty	System
253107	Element, Air Cleaner	1	Air filter	Amazon $43.25 eBay $69.00
253481	Hose, Hump reducer (4 in. to 3 in.)	2	Hose	Amazon eBay
A-253104	Air cleaner assembly	1	Air filter	Amazon Amazon eBay eBay
GM100213	Engine bracket	1	Engine bracket	Amazon eBay
GM101208	Hose barb, crankcase breather	1	Hose	Amazon eBay
GM101211	Thermostat, 6.2L	1	Thermostat	Amazon eBay
GM101223	Sensor, 6.2L oil pressure	1	Sensor	Amazon eBay
GM101269	Filter, 6.2L oil	1	Oil filter	Amazon eBay $49.00
GM102050	Tensioner, 6.2L drive belt	1	Belt	Amazon eBay
GM102769	Hose, Upper radiator	1	Hose	Amazon eBay
GM103656	Hose, coolant SAE J20R2--DI 5/8 in. ID	1	Hose	eBay $23.00
GM104549	Hose, Radiator lower	1	Hose	Amazon eBay
GM104553	Hose, Radiator upper	1	Hose	Amazon eBay
GM104554	Hose, Reducer	1	Hose	Amazon eBay
GM104555	Hose, Reducer	1	Hose	Amazon eBay
GM104787	Air cleaner assembly	1	Air filter	Amazon eBay
GM105068	Water Pump, W/ Gaskets	1	Pump	Amazon eBay $175.00
GM105082	Gasket, Timing Cover	1	Gasket	Amazon eBay
GM105083	Timing Cover	1	Gasket	Amazon eBay
GM105110	Intake Gasket	2	Gasket	Amazon eBay $51.75
GM105112	Head Gasket	1	Gasket	Amazon eBay
GM105118	Oil Pump Assembly, With Pickup Tube	1	Pump	Amazon eBay
GM105119	Gasket, Oil Pan, One Piece	1	Gasket	Amazon eBay
GM105121	Bolt, HFH, 3/8- 16 x 2.25 (Water Pump)	4	Pump	Amazon eBay
GM105125	Gasket, Water Pump	2	Gasket	Amazon eBay
GM105166	Oilcool line, Lower, F6-06-06-8-8-8C-920	1	Hose	Amazon eBay
GM105167	Oilcool line, Upper, F6-06-06-8-8-8C-1432	1	Hose	Amazon eBay
GM14098	Hose, Lower radiator (44 mm ID)	1	Hose	Amazon eBay
GM62309	Element, air cleaner	1	Oil filter	Amazon eBay $91.00
GM88281-1	Load Shed Assembly	1	Load shed assembly	Amazon eBay
GM88993-GR2	Mount, Air Cleaner (6.76”ID)	1	Air filter	Amazon eBay
KG6208	Air Filter, Oil, qts. 5.7L GM89979	1	Spark plug	Amazon eBay $999.99
KOH-48RCLB-AIRF	Kohler 48RCLB Air Filter	1	Air filter	Amazon eBay
KOH-48RCLB-BATTERY	Kohler 48RCLB Battery	1	Battery	buy
KOH-48RCLB-BELT	Kohler 48RCLB Belt	1	Belt	Amazon eBay
KOH-48RCLB-COOL	Kohler 48RCLB Coolant Filter	1	Coolant filter	Amazon eBay
KOH-48RCLB-COOLANT	Kohler 48RCLB Coolant	12.5	Fluid	buy
KOH-48RCLB-FUEL	Kohler 48RCLB Fuel Filter	1	Fuel filter	Amazon eBay
KOH-48RCLB-OIL	Kohler 48RCLB Engine Oil	11.5	Fluid	Amazon eBay
KOH-48RCLB-OILF	Kohler 48RCLB Oil Filter	1	Oil filter	Amazon eBay
KOH-48RCLB-SPARK	Kohler 48RCLB Spark Plug	8	Spark plug	buy
X-312-47	Hose (0.63 in. ID x 36 in.)	1	Hose	eBay
X-312-62	Hose, .63 ID	1	Hose	Amazon eBay $4.00
X-391-19	Connector, 90 degrees (5/8 in. ID hose)	1	Hose	eBay $30.00
X-582-1	Connector, hose (5/8 in. x 1/2 in. MIP brass)	1	Hose	Amazon eBay
X-6014-137	Hose, Wire Insert 3 in. ID	1	Hose	Amazon eBay
X-6380-12	Hose, Charged air cooler	2	Hose	Amazon eBay
246242	voltage reconnection decal		Service part / kit	Amazon eBay $9.67
352945	Block heater (kit GM78529-KP1-QS)	1	Service part / kit	eBay FridayParts $69.99
352946	Block heater (kit GM78529-KP2)	1	Service part / kit	eBay
ADV-9039-A	Weather and Sound Enclosure assembly		Service part / kit	eBay
G4-306			Service part / kit	Amazon
G4-307			Service part / kit	Amazon
GM101207	Valve, PCV	1	Service part / kit	Amazon eBay
GM104703-KP1	Battery heater kit, 120 Volts, heater wrap rating 50 Watts, battery wrap length 864 mm (34 in.), power cord length 483 mm (19 in.), plug cord length 75 mm (3 in.)	1	Service part / kit	Amazon eBay $105.00
GM105063	Connecting Rod	8	Service part / kit	Amazon eBay
GM105067	Camshaft	1	Service part / kit	Amazon eBay
GM105073	Bolt, HFH, 1/4- 20 x .50, WHZ	1	Service part / kit	Amazon eBay
GM105128	Valve, Intake	4	Service part / kit	Amazon eBay
GM105129	Valve, Exhaust	4	Service part / kit	Amazon eBay
GM105130	Valve Spring	8	Service part / kit	Amazon eBay
GM105131	Spring Locator (Valve)	8	Service part / kit	Amazon eBay
GM114539	Wireless Bridge		Service part / kit	Amazon eBay
GM17809	Shield, heat (32 mm ID x 152 mm)	1	Service part / kit	eBay
GM23718	Shield, heat (32 mm ID x 455 mm)	1	Service part / kit	eBay
GM88281	Load Shed Assembly (mounts inside the transfer switch enclosure)	1	Service part / kit	Amazon eBay

Service, wear & replacement parts referenced for this model and its engine — confirm the exact part for your serial number. See the full parts catalog to search and cross-reference.

Fuel consumption

Rating	Load	L/h	gal/h
Prime	100%	10.0	2.67
Standby	25%	8.7	2.3
Standby	50%	14.5	3.83
Standby	75%	20.3	5.36
Standby	100%	12.0	3.2

Available documents

Spec sheet (Kohler)Spec sheet — g4276 (Kohler)Operator's manual (Kohler)Operator's manual — 48rclb engine manual (Kohler)Operator's manual — tp7102 (Kohler)Reference (Kohler)Reference — g6130 (Kohler)Parts manual — TP-7098 (Kohler)Parts manual — kohlerpow datasheet stepid-2757002 (Kohler)Parts manual — tp7098 (Kohler)Service manual — Controllers tt1589 (Kohler)Service manual — adv8954 (Kohler)Service manual — tp7101 (Kohler)Service manual — tp7103 (Kohler)Service manual — tt1587 (Kohler)