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Cummins/Onan N14 Engine

The Cummins/Onan N14 is a 14 L 6-cylinder turbocharged engine rated at 1800 rpm. It powers generator sets from Cummins/Onan, including the DQBA and DQBB. It holds 34 L (9.0 gal) of oil and 51 L (13.5 gal) of coolant.

Also known as: Cummins N14

Part of the Cummins/Onan N14 engine family — 3 variants share parts & fitment.

14.0 L

Displacement

Cylinders

1800 rpm

Rated speed

34.0 L

Oil capacity

On this pageSpecs Generator sets Maintenance FAQ Service intervals Torque & specs Fluids Fault codes Procedures Wiring

Engine specifications

Oil capacity	34.0 L
Coolant capacity	51.0 L
Displacement	14.0 L
Cylinders	6
Aspiration	turbocharged
Rated speed	1800 rpm

Generator sets powered by this engine

Cummins/Onan DQBA Cummins/Onan DQBB

How to read your Cummins/Onan engine serial & model number →

Troubleshooting

Fault codes

Code	Meaning
00100047	Fuel Pump Side
91800ge	Cold Weather Starting Using Starting Fluid
244	Pe
112	Stop

Fault codes and symptom→remedy steps extracted from this engine’s service/owner documentation; verify against the official manual before servicing.

Common problems

Warning, Shutdown, and Non-Automatic lamps are not lit. Digital display shows main menu or selected menu.
Cause: Indicates all engine systems are normal. No corrective action required
Warning lamp lights. 231
Fix: Indicates battery voltage exceeds 32 VDC. Contact an authorized service center.
Shutdown lamp lights. 250
Fix: Indicates PCC memory error. Data corruption of critical operating parameters. Contact an authorized service center.
Non-Automatic lamp flashes.
Cause: Indicates Run/Off/Auto switch is not in the Auto position. This will prevent automatic starting if an automatic transfer switch is used.
Fix: Move the Run/Off/Auto switch to the Auto position for automatic operation.
No AC output voltage.
Fix: Contact an authorized service center.
Engine starts from generator control panel but will not start automatically or from a remote panel.
Cause: (Note: The Run/Off/Auto switch must be in the Auto position for automatic or remote starting). Check the control wiring between the remote switch and the PCC. Contact an authorized service center.
Engine shuts down and will not crank. 102
Cause: Indicates local or remote Emergency Stop.
Fix: To reset the local Emergency Stop button : Pull the button out or turn the switch clockwise (button with arrow) and allow it to pop out. Move the Run/Off/Auto switch to Off. Press the Reset switch. Select Run or Auto, as required.
Engine continues to operate at reduced RPM.
Cause: Indicates that the engine is operating in idle mode. When the set is operating in the RUN mode, grounding the engine idle input causes generator build-up to be inhibited and the engine to be governed at 800 RPM.
Control does not power up when the Run/Off/Auto switch is set to Run or the Self Test switch is pressed.
Cause: There is no DC power to the control.
Fix: A. Check for battery disconnected, discharged, or improperly connected. b. Fuse F1 (20A/32V, Type 3AG) may be open. Replace with the same type. (Fuse is mounted near engine starter/solenoid, see Figure 4-2). Contact an authorized service center.

Compiled from service & troubleshooting documentation across every generator set that uses the Cummins/Onan N14.

Maintenance schedule

Item	Spec	Part #	Interval
Air filter	Air Compressor Air Cleaner Element - Two-Cylinder, Sponge Element	256837		Amazon eBay
Fuel filter	Fuel Shutoff Valve	50121-43698		Amazon eBay
Oil filter	Cummins Part No. 3318853	3318853	250 hr	Amazon eBay $74.95 NAPA $66.59
Battery		—	1500 hr
Belt	Use on v-belts ( 3/8 to 7/8) and v-ribbed belts with 5 ribs or less.	3822524		Amazon eBay
Coolant		—	6000 hr
Coolant filter		—	250 hr
Oil		—	6000 hr
Spark plug		—	6000 hr

Pooled from every document that names this exact engine — confirm the interval and part number against your unit's serial number.

Service intervals

Item	Action	Hours	Months	Notes
Crankcase oil and filter	Change	250 hr	12 mo	Table 7-1. If genset used for prime power, change every 6 months or 250 hours. If standby, change every 12 months or 250 hours, whichever comes first.
Rupture basin leak detect switch	Test		12 mo	Check once a year; in some areas weekly inspections may be required by safety code regulations

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
Clearance	Angular alignment maximum T.I.R.	0.001	inch per inch of radius (center of shaft to indicator axis)	measuring deflection to bolt heads
Clearance	Float switch assembly float lift clearance below C-clip stop	1/8	inch (3 mm)	use a feeler gauge
Clearance	Generator-to-engine angular alignment (T.I.R.)	.001 in. per inch of radius (center of shaft to indicator axis), maximum	in	750 kW gensets and larger
Gap	MPU sensor to flywheel ring gear tooth	back it out one quarter turn	turn	sensor threaded in until it just touches gear tooth
Other	Angular alignment maximum T.I.R.	.001 inches per inch of radius	in/in	center of shaft to indicator axis
Other	Battery specific gravity, fully charged	approximately 1.260	specific gravity	at 80 F (27 C)
Other	Fuel lift height limit	6	feet	(1.8 meters) between fuel lift pump and bottom of dip tube
Other	GOV GAIN default value for paralleling applications	70	%
Other	Maximum cranking voltage drop	2	volts	difference between battery and starter terminals while cranking
Other	REG VHZ (underfrequency roll-off) adjustable range	1 through 50; normal range 7 through 21
Other	Start delay adjustment range	0 to 300	seconds
Other	Stop delay adjustment range	0 to 600	seconds
Other	Under-frequency roll-off threshold (UFRO)	typically 59 Hz for 60 Hz applications and 49 Hz for 50 Hz applications	Hz	AVR UFRO pot preset
Pressure	Engine oil pressure - K19 normal	50-70	psi (345-482 kPa)	run mode
Pressure	Engine oil pressure - K38 normal	45-65	psi (310-448 kPa)	run mode
Pressure	Engine oil pressure - K50 normal	50-70	psi (345-482 kPa)	run mode
Pressure	Engine oil pressure - L10/M11 normal	30-50	psi (207-345 kPa)	run mode
Pressure	Engine oil pressure - NTA 855 normal	35-50	psi (241-345 kPa)	run mode
Pressure	Engine oil pressure - V28 normal	50-90	psi (345-620 kPa)	run mode
Pressure	Engine oil pressure shutdown limit - L10/M11	20	psi (138 kPa)	run mode value
Pressure	Engine oil pressure shutdown limit - L10/M11	8	psi (55 kPa)	idle mode value
Pressure	Engine oil pressure warning limit - L10/M11	12	psi (83 kPa)	idle mode value
Pressure	Engine oil pressure warning limit - L10/M11	25	psi (172 kPa)	run mode value
Pressure	Idle oil pressure shutdown limit (PCC)	12	psi (83 kPa)	idle
Pressure	Idle oil pressure warning limit (PCC)	15	psi (104 kPa)	idle
Pressure	K19 engine idle oil pressure	20	psi (138 kPa)	idle
Pressure	K19 engine normal oil pressure	50-70	psi (345-482 kPa)	normal run
Pressure	K19 oil pressure shutdown/warning limits	shutdown 35 psi (241 kPa) run; warning 40 psi (276 kPa) run; shutdown 10 psi (69 kPa) idle; warning 15 psi (103 kPa) idle	psi (kPa)
Pressure	K38 engine idle oil pressure	20	psi (138 kPa)	idle
Pressure	K38 engine normal oil pressure	45-65	psi (310-448 kPa)	normal run
Pressure	K38 oil pressure shutdown/warning limits	shutdown 35 psi (241 kPa) run; warning 40 psi (276 kPa) run; shutdown 10 psi (69 kPa) idle; warning 15 psi (103 kPa) idle	psi (kPa)
Pressure	K50 engine idle oil pressure	20	psi (138 kPa)	idle
Pressure	K50 engine normal oil pressure	50-70	psi (345-482 kPa)	normal run
Pressure	K50 oil pressure shutdown/warning limits	shutdown 35 psi (241 kPa) run; warning 40 psi (276 kPa) run; shutdown 10 psi (69 kPa) idle; warning 15 psi (103 kPa) idle	psi (kPa)
Pressure	L10/M11 engine idle oil pressure	15	psi (103 kPa)	idle
Pressure	L10/M11 engine normal oil pressure	30-50	psi (207-345 kPa)	normal run
Pressure	L10/M11 oil pressure shutdown limit	20	psi (138 kPa)	run mode value
Pressure	L10/M11 oil pressure shutdown limit	8	psi (55 kPa)	idle mode value
Pressure	L10/M11 oil pressure warning limit	12	psi (83 kPa)	idle mode value
Pressure	L10/M11 oil pressure warning limit	25	psi (172 kPa)	run mode value
Pressure	Low oil pressure service limit while cranking	10	psi	service lubricating system if below
Pressure	Low oil pressure shutdown (Detector)	14	psi (97 kPA)
Pressure	Low oil pressure shutdown threshold	14	psi	less than this value shuts down
Pressure	NTA 855 engine normal oil pressure	35-50	psi (241-345 kPa)	normal run
Pressure	NTA 855 oil pressure shutdown limit	25	psi (172 kPa)	run mode value
Pressure	NTA 855 oil pressure shutdown limit	8	psi (55 kPa)	idle mode value
Pressure	NTA 855 oil pressure warning limit	12	psi (83 kPa)	idle mode value
Pressure	NTA 855 oil pressure warning limit	30	psi (207 kPa)	run mode value
Pressure	Normal engine oil pressure (PCC)	35-50	psi (242-345 kPa)
Pressure	Oil pressure - K19 engine idle	20	psi (138 kPa)	idle
Pressure	Oil pressure - K19 engine normal	50-70	psi (345-482 kPa)	normal operating
Pressure	Oil pressure - K38 engine idle	20	psi (138 kPa)	idle
Pressure	Oil pressure - K38 engine normal	45-65	psi (310-448 kPa)	normal operating
Pressure	Oil pressure - K50 engine idle	20	psi (138 kPa)	idle
Pressure	Oil pressure - K50 engine normal	50-70	psi (345-482 kPa)	normal operating
Pressure	Oil pressure - L10/M11 engine idle	15	psi (103 kPa)	idle
Pressure	Oil pressure - L10/M11 engine normal	30-50	psi (207-345 kPa)	normal operating
Pressure	Oil pressure - NTA 855 engine idle	15	psi (103 kPa)	idle
Pressure	Oil pressure - NTA 855 engine normal	35-50	psi (241-345 kPa)	normal operating
Pressure	Oil pressure - V28 engine idle	20	psi (138 kPa)	idle

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		Refer to the Cummins engine Operation and Maintenance Manual for coolant recommendations/specifications			Balanced mixture of water, antifreeze and coolant additives. Drain and replace every year or after 500 hours whichever occurs first.
Coolant	soft water / E.G. / DCA mixture				Cooling system to be filled with soft water/E.G./DCA mixture (on-site review checklist).
Engine oil		Refer to the Cummins engine Operation and Maintenance Manual for lubricating oil recommendations/specifications			Add oil of the same API viscosity and brand when necessary. Do not operate below low mark or above high mark.
Fuel		Diesel fuel			Do not use zinc coated or copper fuel lines with diesel fuel. Fuel connection at the engine should be made with an approved flexible line.
Fuel	Diesel				Day tank fuel transfer pump maintains reservoir of diesel fuel in the day tank.
Grease	Lithium based grease	Mobilux No. 2 or Shell Alvania R3		2.74 oz (81 ml)	Generator end bearing. Temperature range -22F to +248F (-30C to +120C). Grease should be equally divided between the bearing, bearing cap cavity, and bearing cartridge cavity.
Grease	Lithium based grease, Mobilux No. 2 or Shell Alvania R3		-30°C to 120°C	2.74 oz (81 ml)	End bearing lubricant; grease equally divided between bearing, bearing cap cavity and bearing cartridge cavity.

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
101	IDLE MODE	Indicates that the engine is operating in idle mode. Grounding the engine idle input causes generator build-up to be inhibited and the engine to be governed at 800 RPM.	Warning	Remove ground from engine idle input to return to normal speed and voltage.
102	EMERGENCY STOP	Local or remote Emergency Stop.	Shutdown	Turn the switch clockwise and allow it to pop out (local only); move the Run/Off/Auto switch to Off; press the Reset switch; select Run or Auto as required. Can be reset only at the PCC front panel.
200	LOW OIL PRESSURE	Indicates engine oil pressure has dropped to an unacceptable level.	Warning	If powering critical loads, wait until next shutdown period then follow 201 procedure.
201	LOW OIL PRESSURE	Indicates engine oil pressure has dropped below the shutdown trip point.	Shutdown	Check oil level, lines and filters; replenish if low; reset control and restart; contact service center.
204	OIL PRES SENDER	Indicates that the control has sensed that the engine oil pressure sender is out of its working range.	Warning	Check that the engine oil pressure sender is properly connected. Contact service center.
210	LOW COOLANT TEMP	Warning occurs when engine coolant temperature is 70°F (21°C) or lower.	Warning	Indicates engine coolant heater is not operating or is not circulating coolant. Check coolant heater power supply, low coolant level, and heater element current draw.
211	HIGH COOLANT TEMP	Indicates the engine coolant temperature is getting close to the recommended maximum temperature limit: 215° F (102° C) − standby or 207° F (97° C) − primary.	Warning	Reduce load; check air inlets/outlets and remove obstructions.
212	HIGH COOLANT TEMP	Indicates engine has overheated (coolant temperature has risen above the shutdown trip point: 215 F (102 C) - standby or 207 F (97 C) - primary).	Shutdown	Check for obstructions to cooling airflow; check fan belt; check coolant mixture; check blower fan and circulation pumps; reset control and restart.
213	COOLANT SENDER	Resistance of the coolant temperature sender is out of range.	Warning	Contact an authorized service center.
214	LOW COOLANT LVL	Indicates engine coolant level has fallen below the trip point.	Warning	Check coolant level in radiator and coolant recovery bottle; replenish if low; look for leaks.
215	LOW COOLANT LVL	Indicates engine coolant level has fallen below the trip point.	Shutdown	Allow engine to cool; check coolant level and replenish; look for leaks and repair; reset and restart. Shutdown will not occur in Idle mode.
220	MAG PICKUP	Mag pickup speed indication not sensed or does not match generator set output frequency.	Shutdown	Restart and check RPM; check PCC model setting; inspect and test MPU.
221	FAIL TO CRANK	Possible fault with control or starting system.	Shutdown	Check fuse F3 on the Engine Interface board; check battery cable connections; recharge or replace the battery.
222	OVERCRANK	Possible fuel system problem.	Shutdown	Check for empty fuel tank, leaks, plugged fuel lines; replace dirty fuel or air filter; reset and restart.
223	OVERSPEED	Indicates engine has exceeded normal operating speed. (115% ±1% of nominal).	Shutdown	Contact an authorized service center.
224	FAIL TO SYNCHRONIZE	Generator set has not synchronized to the system bus within the allowable time frame.	Warning	Check governor system stability; adjust governing and synchronizer parameters; check fuel system.
226	FAIL TO CLOSE	Paralleling breaker has been given a signal to close, but has not closed properly.	Shutdown	Verify breaker charging mechanism; check close signal; verify auxiliary contact signals.
230	LOW DC VOLTAGE	Indicates battery voltage is below 10 VDC.	Warning	Recharge or replace the battery; check the battery charger fuse. Clean and tighten battery cable connections. Check engine DC alternator; replace if normal charging voltage is not obtained. Check float level if applicable.
231	HIGH DC VOLTAGE	Indicates battery voltage exceeds 32 VDC.	Warning	Lower battery charger float level if applicable; check engine DC alternator.
232	WEAK BATTERY	Indicates battery voltage drops below 60% of nominal for two seconds, during starting.	Warning	See Warning message 230, LOW DC VOLTAGE.
240	LOW FUEL−DAY	Indicates day tank fuel supply is running low.	Warning	Check fuel supply and replenish as required.
241	LOW FUEL	Low fuel signal received.	Warning	Check fuel supply and replenish; check for short to ground in external wiring.
250	EEPROM ERROR	PCC memory error; data corruption of critical operating parameters.	Shutdown	Perform the initial start setup procedure; if the set shuts down on the same EEPROM ERROR message, replace the digital board (A32).
251	EEPROM ERROR	PCC memory error; data corruption of noncritical operating parameters.	Warning	Perform the adjustment procedures; if the same message occurs, perform calibration procedures; if the message persists, replace the digital board (A32).
252	EEPROM ERROR	PCC memory error; data corruption of noncritical operating parameters.	Warning	Verify values/choices selected and repeat the save operation; if the same message occurs, replace the digital board (A32).
260	CUSTOMER FAULT 1	When this customer defined input is closed to ground, the corresponding fault message is displayed. Programmable to initiate a shutdown or a warning.	Warning	Isolate source of false signal; repair external wiring or replace A34.
261	GROUND FAULT	When a customer defined input is closed to ground, the corresponding fault message is displayed. Default message; editable for customer site requirements.	Warning	Isolate source of false signal; repair external wiring or replace A34.
262	RUPTURE BASIN	When a customer defined input is closed to ground, the corresponding fault message is displayed. Default message; editable for customer site requirements.	Warning	Isolate source of false signal; repair external wiring or replace A34.
263	HIGH GEN TEMP	When a customer defined input is closed to ground, the corresponding fault message is displayed. Default message; editable for customer site requirements.	Warning	Isolate source of false signal; repair external wiring or replace A34.
270	PHASE ROTATION	The phase relationship between the generator set and the system bus is not matched.	Shutdown	Verify genset phase rotation matches bus; verify control wiring to bus PT module.
272	FIRST START	PowerCommand control is not receiving a proper signal from the system master first start sensor.	Warning	Verify Master First Start Sensor and interconnection wiring.
301	HIGH AC VOLTAGE	One or more phase voltages exceeded 130% of nominal, or exceeded 110% of nominal for 10 seconds.	Shutdown	Set display to GEN, VOLTS, L-N; determine if the output voltage the control sees is low or high; isolate PCC/alternator/excitation circuit.
303	LOW AC VOLTAGE	One or more phase voltages dropped below 85% of nominal for 10 seconds.	Shutdown	Contact an authorized service center.
313	UNDER FREQUENCY	Indicates that engine speed has dropped below 90% of nominal for 10 seconds. Five seconds before shutdown, a Load Dump signal is initiated.	Shutdown	Contact an authorized service center. Load Dump signal initiated five seconds before shutdown.
320	OVERCURRENT	Indicates that generator output current has exceeded 110% of rated for 60 seconds.	Warning	Contact an authorized service center.
321	OVERCURRENT	Indicates that generator output current has exceeded 110% of rated, and that a PCC time/current calculation has initiated an overcurrent shutdown.	Shutdown	Contact an authorized service center.
322	SHORT CIRCUIT	Indicates that generator output current has exceeded 175% of rated.	Shutdown	Contact an authorized service center.
330	OVERLOAD	Three-phase power output exceeds 105% of standby (or 115% of prime) rating.	Warning	Check load and load lead connections.
335	REVERSE POWER	Power is flowing into the generator set rather than out from the unit.	Shutdown	Verify CT connections, load sharing lines, and generator set frequency/voltage.
337	LOSS OF EXCITATION	Alternator excitation system is improperly adjusted or has failed.	Shutdown	Check output voltage calibration, load sharing lines, and leading power factor loads.
FAULT 1	Fault 1 (Red)	Engine shut down because of a customer-connected system fault; part of a 10 second time delay shutdown circuit.	Shutdown	Service as required by the customer-supplied fault indicating switches.
FAULT 2	Fault 2 (Red)	Engine shut down because of a customer-connected system fault; part of a non-time delay shutdown circuit.	Shutdown	Service as required by the customer-supplied fault indicating switches.
GF	Ground Fault Alarm (Optional)	Ground fault relay monitors neutral to ground connection and line to neutral, activating a fault alarm when the connection is broken or a ground fault is sensed.	Warning	Clear fault condition by pushing the Run/Stop (Reset)/Remote switch to Reset (auto reset link set at factory).
HET	High Engine Temperature (Red)	Engine shut down because of excessively high engine coolant temperature (greater than 230 deg F).	Shutdown	Check coolant level and leaks; service cooling system; reset engine control.
LET	Low Engine Temperature (Yellow)	Engine temperature is less than 70 deg F and the engine might not start.	Warning	Plug in, repair or install engine coolant and oil heaters.
LOP	Low Oil Pressure (Red)	Engine shut down because of excessively low engine oil pressure (less than 14 psi).	Shutdown	Check oil level and oil leaks; service lubricating system; reset engine control.
LOW FUEL	Low Fuel (Yellow)	Fuel level in the supply tank has dropped below the reserve necessary to run the set at full load for the prescribed number of hours.	Warning	Fill the main fuel supply tank with the appropriate grade of fuel.
OC	Overcrank (Red)	Engine shut down because it did not start during the timed cranking period (approximately 75 seconds, including two rest periods).	Shutdown	Service the set as necessary; reset engine control.
OS	Overspeed (Red)	Engine shut down because of overspeed.	Shutdown	Adjust the Electronic Overspeed Module; check governor for binding; reset engine control.
PRE-HET	Pre High Engine Temperature (Yellow)	Engine coolant temperature is abnormally high (greater than 220 deg F).	Warning	Shut down if possible or disconnect non-critical loads; service cooling system.
PRE-LOP	Pre Low Oil Pressure (Yellow)	Engine oil pressure is abnormally low (less than 20 psi).	Warning	Shut down if possible or disconnect non-critical loads; service lubricating system.
RUN	Run (Green)	Generator set is running and the starter has been disconnected.	Info
SWITCH OFF	Switch-off (Flashing Red)	The Run/Stop/Remote switch is in the Stop position, preventing remote automatic operation.	Info	Push the Run-Stop-Remote switch to Remote.

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

Procedures

Aligning Generator with Engine (Angular Alignment) adjustment

⚠ Accidental starting of the generator set during this procedure presents the hazard of severe personal injury or death.

Tools: Dial indicator, Shims

Disconnect the negative (-) battery cable(s) before beginning.
Fasten a dial indicator to the generator shaft or cooling fan with the sensing point on the capscrew head or flat surface of the drive disc at the bolt circle diameter.
Bar the engine over in a clockwise rotation as viewed from engine flywheel; do not allow it to roll back on compression.
Determine the total indicator reading (T.I.R.) as the sum of the maximum positive and negative dial indicator readings over one revolution.
Measure the distance from the center of the generator shaft to the indicator measuring point.
Measure the distance from the generator side of the flex discs to the center of the generator mounting bolt.
Compare the distances; multiply this ratio times one half the T.I.R. to approximate the amount of shims to remove or add.

Angular Alignment Procedure adjustment

⚠ Accidental starting of the generator set during this procedure presents the hazard of severe personal injury or death. Make sure to disconnect the negative (-) battery cable(s) before beginning.

Tools: Dial indicator, Wooden shims

Disconnect the negative (-) battery cable(s) before beginning.
Fasten a dial indicator to the generator shaft or cooling fan with sensing point on capscrew head or flat surface of drive disc at bolt circle diameter.
Bar the engine over in a clockwise rotation as viewed from engine flywheel; do not allow it to roll back on compression.
Record maximum positive and negative dial indicator readings as the engine completes one revolution.
T.I.R. equals the sum of the maximum positive and negative readings.
Maximum T.I.R. should not be more than .001 inch for each inch of radius.
Remove equal shims from under both generator mounting feet to lower the generator.

Angular Alignment Procedure (Generator to Engine) adjustment

⚠ Accidental starting during this procedure presents the hazard of severe personal injury or death.

⚠ Do not bar engine over by prying on fan blade.

Tools: dial indicator

Disconnect the negative (-) battery cable(s) before beginning.
Fasten a dial indicator to the generator shaft or cooling fan with sensing point resting on the drive disc capscrew head/flat surface at the bolt circle diameter.
Bar the engine over in a clockwise rotation as viewed from the engine flywheel; do not allow it to roll back on compression at the end of travel of each reading.
Record the total indicator reading (T.I.R.) as the sum of the maximum positive and negative dial indicator readings over one engine revolution.
Compare the measured T.I.R. to the maximum allowed (.001 in. per inch of radius from center of shaft to indicator axis); add or remove shims under the generator mounting feet to correct.

Axial Alignment Procedure (Generator to Engine) adjustment

Tools: dial indicator

Fasten a dial indicator holding device to the skid base, engine block, or generator shell with the sensor point resting on the generator shaft hub.
Bar the engine over in a clockwise rotation through a couple of rotations, recording indicator readings at eight equally spaced points around the shaft diameter to obtain axial T.I.R.
Reduce the measured T.I.R. runout by one half if excessive vibration remains after angular alignment.

Governor Calibration Checks adjustment

Tools: Frequency meter or tachometer, Jumper wire

Start the generator set.
Adjust engine no-load speed to the desired allowable speed droop using the Run Speed potentiometer.
With no load, turn GAIN clockwise slowly until engine speed oscillates.
Reduce GAIN slowly counterclockwise until engine speed is stable.
Upset the governor by momentarily shorting terminals 7 and 10 on the governor control.
Apply and remove loads to check generator set response.

HC4-7 Axial Alignment Procedure adjustment

Tools: Dial indicator with magnetic base or clamp

Check only when an objectionable vibration is present.
Fasten dial indicator holding device to skid base, engine block, or generator shell with magnetic base or clamp.
Position sensor point on the generator shaft hub.
Bar the engine over in a clockwise rotation as viewed from engine flywheel through a couple of rotations.
Record indicator readings in eight equally spaced points around the shaft diameter.
Remove the capscrews connecting drive discs and flywheel and mark discs and flywheel.
Rotate engine or generator so drive disc holes are repositioned 180 degrees from original location.
Put capscrews back in and retorque. Recheck shaft alignment.
If runout unchanged, rotate discs to 30, 60 or 90 degrees from original location.
If T.I.R. does not improve, inspect flywheel pilot and drive disc runouts.

P7 Axial Alignment Procedure adjustment

Check only when an objectionable vibration is present.
Remove the capscrews connecting drive discs and flywheel.
Mark the drive discs and flywheel with respect to each other.
Rotate engine or generator so drive discs holes are repositioned two bolt holes from original location.
Put capscrews back in and retorque. Recheck/record vibration levels.
Repeat this test until drive disc holes are repositioned 180 degrees from original location.
Review vibration data and position drive disc in lowest recorded level location.

UFRO Adjustments adjustment

⚠ Use an insulated handle screw driver to prevent electrical shock.

Tools: Insulated handle screwdriver, Frequency meter or tachometer

Make a note of the no-load frequency.
Determine roll-off frequency by turning the governor speed pot until the LED lights; if okay go to step 5.
Adjust the governor speed pot to the proper roll-off frequency.
Turn the UFRO pot until LED goes off, then slowly turn it back until the LED just goes on.
Adjust the governor speed pot back to the initial frequency setting.

Voltage and Voltage Stability Adjustments adjustment

⚠ Touching uninsulated high voltage parts inside the control and power output boxes can result in severe personal injury or death.

Tools: Insulated handle screwdriver, AC voltmeter

Use the control panel mounted voltage trimmer, if provided, for small voltage adjustments.
Measure generator output voltage while running without load at nominal frequency.
If trimmer is insufficient, lock it at midpoint.
Turn the VOLTS pot fully counterclockwise and the STABILITY pot to its midpoint.
If the red LED lights, refer to Jumper Reconnections and UFRO Adjustments.
Turn the VOLTS pot clockwise until rated voltage is obtained.
If voltage becomes unstable with a large load, turn the STABILITY pot clockwise until stable.
Check and readjust the VOLTS pot each time the STABILITY pot is readjusted.

Generator/PCC Control Isolation Procedure diagnostic

⚠ HIGH VOLTAGE. Touching uninsulated high voltage parts inside the control box can result in severe personal injury or death.

Tools: Voltmeter, Jumpers, 12 volt battery

Throw the line circuit breaker OFF and shut down the set.
Remove accessory box cover; remove plug P10 from A37 J10.
Prepare to measure output voltage across generator terminals.
Connect 12V battery jumpers to X (P10-6 red) and XX (P10-3 brown).
Check polarity; incorrect polarity makes the test inconclusive.
Start set and connect battery negative to the XX lead.
Rated or higher balanced voltage means generator circuitry is OK.
Unbalanced voltage: troubleshoot main stator; low voltage: exciter/field.

Insulation Resistance (Megger) & Polarization Index (PI) Testing diagnostic

⚠ The windings of medium-voltage (601 through 15,000 volts) generator sets must be dry before the generator is operated.

Tools: Megger or insulation resistance meter, Grounding cluster, High voltage gloves

Perform the Generator Set Grounding Procedure.
Disconnect plug J10 from A37 and AC control leads 4,5,6,7,8.
If RTD option installed, ground all six RTD temperature leads (18 leads).
Perform Insulation Resistance Test and PI Test for desired windings.
Megger test: apply voltage for up to one minute.
PI test: apply voltage for ten minutes; record 1-minute and 10-minute readings.
PI ratio of 2 or greater is good for new and in-service sets.
Investigate and correct low readings before returning set to service.

Megger and PI Test diagnostic

⚠ Medium-voltage (601 to 15,000 volts) windings must be dry before the generator is operated.

Tools: Megger or Insulation Resistance Meter, Wheatstone bridge or digital ohmmeter, Grounding Cluster

Perform the Generator Set Grounding Procedure.
Disconnect plug J10 from the voltage regulator output module and the AC control leads (marked 4, 5, 6, 7, 8).
If RTD option installed, ground all six RTD temperature leads (18 leads total).
Perform the Winding Resistance Test for the desired windings.
Perform the Insulation Resistance (Megger) Test and PI Test for the desired windings.
Megger test: apply voltage for up to one minute.
PI test: apply voltage for ten minutes; record resistance at one minute and ten minutes.
PI is the ten-minute reading divided by the one-minute reading; ratio of two or greater is good.

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

Phase	Connection	Leads	Notes
	12 lead generator sets	Load wires are routed through the CTs	Reconnectable gensets (12 leads) have dual secondary CTs (3 pins); CT wire 2/3 to pin 2 (high voltage) or pin 3 (low voltage).
	6 lead generator sets	Generator output leads are routed through the CTs	Non-reconnectable gensets (6 leads) have single secondary CTs (2 pins).
	Cummins PowerCommand generic AC Reconnect Wiring Diagram 625-2755 (Rev. D) and 625-3100 (Rev. F)		Applies to models DFAA, DFAB, DFAC, DFBF, DFCB, DFCC, DFEB, DFEC, DFFB, DFGA, DFGB, DFJA, DFJB, DFJC, DFJD, DFLB, DFLC, DFLD, DFMB (625-2755) and models DFAA-DFMB plus DFCE, DFED, DQAA, DQAB, DQBA, DQBB (625-3100).
A (U)	CT21	U load leads (A phase)	CT dot must face the generator; CT terminal 1 connects to metering circuit, terminal 2/3 to ground.
B (V)	CT22	V load leads (B phase)	CT dot must face the generator; terminal 1 to metering circuit, terminal 2/3 to ground.
C (W)	CT23	W load leads (C phase)	CT dot must face the generator; terminal 1 to metering circuit, terminal 2/3 to ground.

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

Parts cataloged across the Cummins/Onan N14 family

110

Part #	Description	Category
3163196	torque wrench adapter	Adapter
256837	Air Compressor Air Cleaner Element - Two-Cylinder, Sponge Element	Air filter
3822524	Use on v-belts ( 3/8 to 7/8) and v-ribbed belts with 5 ribs or less.	Belt
0300-4623-09	DFCB (600V)	Current transformer
0300-4623-10	DFCC (600V)	Current transformer
0300-4623-24	DFCB BR (0-480V)	Current transformer
0300-4623-27	DFCC BR (0-480V)	Current transformer
1920090	ECM	ECM / ECU
19801556	ECM	ECM / ECU
49200083	ECM	ECM / ECU
19801564	CENTRY™ STC Actuator Lead Wire	Electronic fuel control valve
19200074	Buzzer	Engine harness adaptor cable
19800109	Engine Speed Sensor	Engine speed sensor
19801560	Fuel Block	Fuel block
50121-43698	Fuel Shutoff Valve	Fuel filter
19801565	Fuel Pressure Sensing Line	Fuel pressure sensing line
1920096	Fuel Pump Gear Pump	Fuel pump
08600043	sea water pump gasket	Gasket
08600042	sea water pump housing	Housing
08600119	sea water pump impeller	Impeller
3822697	Injector Puller	Injector
3823348	STC Injector Tappet Retaining Tool (IBC method)	Injector
3823579	CELECT™ Injector Puller	Injector
3824653	STC Injector Puller	Injector
M-3070113	Injector Sleeve	Injector
M-3072485	Injector Plunger Link	Injector
M-3078226	Injector Plunger Link	Injector
19801567	Main Engine Harness	Main engine harness
3318853	Combination Full-Flow/Bypass Lubricating Oil Filter	Oil filter
19100001	Idle Shutdown Feature	Service part / kit
19100064	Automotive Governor with Droop	Service part / kit
19160001	Automotive Governor	Service part / kit
19200073	WARNING and STOP lights in the cab panel	Service part / kit
19200075	Maintenance monitor data (Cumulative Data, Trip Data, Idle Data, PTO Data)	Service part / kit
19200084	Fan Clutch 2 Enable	Service part / kit
1920086	Fuel Shutoff Valve	Service part / kit
1920089	Cooling Plate	Service part / kit
1920091	Engine Wiring Harness (actuator amp connector)	Service part / kit
1920092	OEM Wiring Harness	Service part / kit
1920093	Engine Mounted Service Tool Datalink	Service part / kit
1920094	Fuel In	Service part / kit
1920095	Fuel Out	Service part / kit
19400220	Engine Brake Solenoid Valve	Service part / kit
19601595	ADVANTAGE™	Service part / kit
19801598	ADVANTAGE™ POINT	Service part / kit
19801602	Transient Black Smoke Control	Service part / kit
19801603	CENTRY™ Plus	Service part / kit
19801610	N14 Section 1 - Operating Instructions	Service part / kit
3376592	Inch Pound Torque Wrench	Service part / kit
3823097	High-temperature Anti-Seize Compound	Service part / kit
3823461	Chip Removal Tool	Service part / kit
49100029	Fan Clutch 2 Enable	Service part / kit
49200053	PTO Set	Service part / kit
49601601	Torque Signal	Service part / kit
49801597	Power Output	Service part / kit
49801599	Low Speed High Speed	Service part / kit
49801603	AFC CONTROLLED FUEL	Service part / kit
C2800	Fleetguard® refractometer	Service part / kit
M-3066736	Valve Spring Housing	Service part / kit
M-3066738	Valve Spring	Service part / kit
M-3067426	Valve Spring Retainer	Service part / kit
M-3070184	Cup Retainer	Service part / kit
M-3071967	Filter Screen	Service part / kit
M-3072486	Link Retainer	Service part / kit
M-3072819	– Spring Housing Spacer	Service part / kit
M-3072821	– Spring Guide	Service part / kit
M-3072822	– Socket Set Screw	Service part / kit
M-3072823	Spring Housing Spacer Assembly	Service part / kit
M-3073244	Cup Retainer	Service part / kit
M-3075613	Socket Head Cap Screw	Service part / kit
M-3076068	Ball Check	Service part / kit
M-3076071	Spray Tip Assembly	Service part / kit
M-3076256	Wiring Harness	Service part / kit
M-3080766	Coupling Retainer	Service part / kit
M-3081342	Plunger Coupling	Service part / kit
M-3081371	Upper Plunger Spring – Female	Service part / kit
M-3081388	Upper Plunger Spring – Male	Service part / kit
M-3083863	Plunger Coupling	Service part / kit
M-3087552	Upper Plunger – Male	Service part / kit
M-3087791	Spray Tip Assembly	Service part / kit
M-3088175	Spray Tip Assembly	Service part / kit
M-3409978	Spray Tip Assembly	Service part / kit
M-3411340	Plunger Coupling Spring	Service part / kit
M-3411388	Spray Tip Assembly	Service part / kit
M-3411690	Spray Tip Assembly	Service part / kit
M-3411694	Spray Tip Assembly	Service part / kit
M-3411711	Plunger and Barrel – Male	Service part / kit
M-3411775	Spring Retainer	Service part / kit
M-3609852	Spray Tip Assembly	Service part / kit
M-3609855	Spray Tip Assembly	Service part / kit
M-3609861	Spray Tip Assembly	Service part / kit
M-3800419	All manufacturer’s names, symbols and descriptions are used for reference only and it	Service part / kit
19801568	Rail Pressure Sensor	Rail pressure sensor
08500039	sea water pump screw	Screw
M-3034408	Control Valve O-Ring	Seal
M-3068959	Barrel O-Ring	Seal
M-3070136	O-Ring Seal Top	Seal
M-3070137	O-Ring Seal Middle	Seal
M-3070138	O-Ring Seal Bottom	Seal
M-3075658	Solenoid O-Ring	Seal
M-3080421	Sealing Washer	Seal
1920087	Oil Pressure Sensor	Sensor
1920088	Intake Manifold Pressure Sensor	Sensor
1920097	Oil Temperature Sensor	Sensor
1920098	Engine Position Speed Sensor (behind lubricating oil pump)	Sensor
1920100	Coolant Level Sensor (in radiator) - Optional	Sensor
1920101	Intake Manifold Temperature Sensor	Sensor
1920102	Ambient Air Pressure Sensor (when required)	Sensor
1920099	Coolant Temperature Sensor (in thermostat housing)	Thermostat
50121-43700	Thermostat	Thermostat

Parts cataloged across all variants of this engine family — verify the exact part fits your specific variant and serial number before ordering.

Aftermarket parts that fit this engine

0327-1507 FridayParts $499.99 FP-XP-0041835

Parts listed by aftermarket suppliers as fitting this engine — leads compiled from supplier catalogs; verify the exact part for your serial number.

Common questions

What is the oil capacity of the Cummins/Onan N14?

The Cummins/Onan N14 engine has an oil capacity of 34.0 liters.

What is the displacement of the Cummins/Onan N14?

The Cummins/Onan N14 has a displacement of 14.0 liters with 6 cylinders.

Which generators use the Cummins/Onan N14 engine?

The Cummins/Onan N14 powers 2 generator set(s), including Cummins/Onan DQBA, Cummins/Onan DQBB.

How often should you change the oil in the Cummins/Onan N14?

The Cummins/Onan N14 oil change interval is every 6000 hours.

What is a common problem with the Cummins/Onan N14 engine?

A commonly reported issue on generators using the Cummins/Onan N14 is: Warning, Shutdown, and Non-Automatic lamps are not lit. Digital display shows main menu or selected menu.. Cause: Indicates all engine systems are normal. No corrective action required.