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Cummins/Onan 6A3.4 Engine

The Cummins/Onan 6A3.4 is an engine rated at 1800 rpm. It powers generator sets from Cummins/Onan, including the DGAC, DGAD and MDL6. It holds 8.5 L (2.2 gal) of oil and 12.5 L (3.3 gal) of coolant.

Also known as: Cummins 6A3.4, 6A3.4

1800 rpm

Rated speed

8.5 L

Oil capacity

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

Engine specifications

Oil capacity	8.5 L
Coolant capacity	12.5 L
Rated speed	1800 rpm

Generator sets powered by this engine

Cummins/Onan DGAC Cummins/Onan DGAD Cummins/Onan MDL6

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

Common problems

No AC output voltage at rated engine RPM
Cause: Control panel field breaker CB21 off
Fix: Push to reset breaker; if voltage is unstable, high or low, or causes breaker to trip, see Flow Charts B, C, D or E
Engine will not crank.
Cause: Fault lamp on.
Fix: Correct fault and reset control.
Unstable output voltage, engine speed stable
Cause: Broken wires or loose connections on voltage regulator assembly
Fix: Repair as required
Engine does not crank
Cause: Battery dead
Fix: Check battery per Checkout [A] and recharge or replace; check battery charger operation per Checkout [C]
The FAULT 1 or FAULT 2 fault lamp lights. Engine shuts down immediately, engine runs for several seconds and then shuts down, or engine continues to run. FAULT 1
Cause: The standard undesignated fault functions are programmed to shut down the set when a fault is sensed. Fault 1 is time delayed while Fault 2 is immediate. The nature of the fault is an optional selection that is determined when the set installation is designed. The undesignated fault functions may also be programmed for non-shutdown or non-time delay.
Engine cranks but does not start
Cause: Fuel supply system problem
Fix: Check fuel tank level, shutoff valves, fuel lines and connections, fuel filters, transfer pump and injection pump; fuel flow should be steady from fuel return line
The fault lamp lights. Engine shuts down immediately, engine runs for several seconds and then shuts down, or engine continues to run. FAULT 1 or FAULT 2
Fix: Engine gauges show oil pressure, engine temperature, and frequency (speed) are within normal limits.
SWITCH OFF lamp flashes.
Cause: Indicates Run/Stop/Remote switch is in the Stop position which will prevent automatic starting if an automatic transfer switch is used.
Fix: Move the Run/Stop/Remote switch to the Remote position for automatic starting.
Same features as Fault 1 (Normally set for non-timed shutdown). FAULT 2 (red)
PRE LO OIL PRES lamp lights. Engine continues to operate.
Cause: Indicates engine oil pressure has dropped to 20 psi (138 kPa).
Fix: If generator is powering critical loads and cannot be shut down, wait until next shutdown period and then follow step 5 procedure. If engine can be stopped, follow procedures in step 5.
PRE HI ENGINE TEMP lamp lights. Engine continues to operate.
Cause: Indicates engine has begun to overheat and engine temperature has risen to approximately 202°F (94°C).
Fix: If generator is powering non-critical and critical loads and cannot be shutdown, use the following: Reduce load if possible by turning off non-critical loads; Check air inlets and outlets and remove any obstructions to airflow; Open doors or windows in generator area to increase ventilation. If engine can be stopped, follow procedure in step 3.
OVERCRANK lamp lights and engine stops cranking. or Engine runs, shuts down, and LO OIL PRES lamp lights.
Cause: Indicates possible fuel system problem.
Fix: Check for empty fuel tank, fuel leaks, or plugged fuel lines and correct as required; Check for dirty fuel filter and replace if necessary (see MAINTENANCE section); Check for dirty or plugged air filter and replace if necessary (see MAINTENANCE section); Refer to Step 5; Reset the control and restart after correcting the problem. Contact an authorized dealer or distributor for service if none of the above.
Output voltage too high or low
Cause: Engine not running at correct RPM
Fix: Set RPM per instructions in appropriate engine manual
NO AC output voltage.
Cause: Field breaker is tripped.
Fix: Reset breaker. Contact an authorized dealer or distributor if voltage build up causes breaker to trip.
LO OIL PRES lamp lights. Engine shuts down
Cause: Indicates engine oil pressure has dropped to 14 psi (97 kPa).
Fix: Check oil level, lines and filters. If oil system is okay but oil level is low, replenish. Reset control and restart. Contact an authorized dealer or distributor if oil pressure is not in the range of 30 to 55 psi (206 to 379 kPa).

Compiled from service & troubleshooting documentation across every generator set that uses the Cummins/Onan 6A3.4.

Service intervals

Item	Action	Hours	Months	Notes
Valve clearance	Adjust	35 hr		First service — Table 4-1 Note 2: perform after first 35 hours of operation on new sets; Note 4: contact Onan authorized service dealer
Battery electrolyte level	Check	200 hr		Fill cells to bottom of filler neck; add distilled water
Crankcase oil	Change	50 hr		First service — After first 50 hours of operation on new generator sets.
Crankcase oil and valve lash	Change	50 hr		First service — Break-in: drain and replace crankcase oil and reset valve lash after first 50 hours on new gensets
Valve lash clearance	Check	50 hr		First service — See Note 3; perform after first 50 hours of operation on new sets.
Crankcase breather cap (turbo)	Clean	400 hr		DGAE turbocharged engines; clean with solvent and allow to dry.
Generator bearing	Inspect	1000 hr		Inspect for evidence of outer case rotation every 1000 hours.
Cooling system	Drain		12 mo	Drain, flush, and refill once a year.
Cooling system pressure cap	Replace		24 mo	Replace every two years or sooner if it malfunctions
Generator bearing	Replace	10000 hr	60 mo	Standby: every five years.

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	Trailer brake actuator stroke length	1	inch (25 mm)	maximum before brake shoe readjustment
Gap	Float switch test feeler gauge	0.125	inch (3 mm)	between float and C-clip stop
Gap	Magnetic pickup adjustment	1/2 turn out from tooth	turn	after contact with flywheel tooth
Gap	Overspeed switch air gap	0.005	inch (0.13 mm)	minimum
Gap	Overspeed switch air gap	not less than 0.005	inch (0.13 mm)
Gap	Overspeed switch magnetic air gap	0.005	inch	minimum
Gap	Overspeed switch magnetic air gap	0.13	mm	minimum
Other	Battery charge threshold	1.215		charge if reading is below
Other	Battery electrolyte specific gravity	1.260	specific gravity	fully charged at 80°F (27°C)
Other	Battery electrolyte specific gravity	about 1.260	specific gravity	fully charged at 80°F (27°C)
Other	Battery electrolyte specific gravity, fully charged	1.260	specific gravity	80°F (27°C)
Other	Battery specific gravity fully charged	1.260		corrected to 80°F (27°C)
Other	Brake shoe adjustment	10	clicks	back off from point wheel cannot be turned by hand
Other	Control heater element power	75	watts at 120 VAC
Other	Cooling system fill rate	3	gallons/minute
Other	Cycle cranking	15 seconds crank, 15 seconds rest, 3 cycles	seconds	12-lamp control
Other	Fan belt tension	60	lbs (267 N)
Other	Heavy duty air cleaner air drying time	24	hours	minimum
Other	Overcrank cranking limit	75	seconds
Other	Pump belt tension	60	pounds (267 N)	measured with belt tension tool
Pressure	Control power latch S6	5	psi	closes at
Pressure	Cooling system pressure cap rating	7	psi (48 kPa)
Pressure	Engine oil pressure (at operating temperature)	30 to 55	psi (207 to 380 kPa)	engine at operating temperature
Pressure	Engine oil pressure (normal)	30 to 55	psi (207 to 380 kPa)	engine at operating temperature
Pressure	Low oil pressure fault switch actuation	14	psi (97 kPa)	pressure drops below
Pressure	Low oil pressure shutdown	14	psi (97 kPa)
Pressure	Low oil pressure shutdown	below 14	psi (97 kPa)	fault time delayed about 10 seconds following starter disconnect and inhibited during cranking
Pressure	Low oil pressure switch S7 set point	14	psi	closes at
Pressure	Oil pressure gauge range	0 to 100	psi
Pressure	Oil pressure gauge range	0 to 700	kPa
Pressure	Pre-low oil pressure alarm	20	psi (137 kPa)	or less
Resistance	Actuator coil resistance	1 ±10%	ohm	at 77°F (25°C); leads disconnected
Resistance	Battery specific gravity, recharge threshold	1.215	specific gravity	charge battery if reading is below
Resistance	Commutating reactor L21, leads 1 and 2	330 to 390	milliohm	77°F (25°C)
Resistance	Control heater element resistance	192	ohms	dissipates 75 watts at 120 VAC
Resistance	Exciter rotor ground insulation	1	megohm	minimum; less indicates defective ground insulation
Resistance	Exciter rotor lead pairs T1-T2, T2-T3, T1-T3	486 to 594	milliohms	77°F (25°C)
Resistance	Exciter rotor lead pairs T1-T2, T2-T3, T1-T3	581 to 710	milliohms	77°F (25°C)
Resistance	Exciter rotor winding resistance	0.54	ohms	at 77°F (25°C), ±10%
Resistance	Exciter rotor winding resistance	0.54 ±10%	ohms	at 77°F (25°C)
Resistance	Exciter rotor winding resistance	0.645	ohms	at 77°F (25°C), ±10%
Resistance	Exciter rotor winding resistance	0.645 ±10%	ohms	at 77°F (25°C)
Resistance	Exciter stator field leads F1+ to F2-	11 to 14	ohms	77°F (25°C)
Resistance	Exciter stator field leads F1+ to F2-	13 to 16	ohms	77°F (25°C)
Resistance	Exciter stator insulation resistance to lamination	100,000	ohms	minimum; 500 VDC or more
Resistance	Exciter stator insulation to laminations (Megger 500 VDC or more)	100,000	ohms	minimum
Resistance	Exciter stator insulation to laminations (ohmmeter)	1	megohm	minimum (1,000,000 ohms)
Resistance	Exciter stator winding resistance	12.4 ±10%	ohms	at 77°F (25°C)
Resistance	Exciter stator winding resistance	14.5 ±10%	ohms	at 77°F (25°C)
Resistance	Exciter stator winding resistance, 4A2.3/6A3.4/6AT3.4	14.5	ohms	at 77°F (25°C), ±10%
Resistance	Exciter stator winding resistance, DGAB/DGAC/DGAD/DGAE	12.4	ohms	at 77°F (25°C), ±10%
Resistance	Exciter stator winding resistance, DL4	20.0	ohms	at 77°F (25°C)
Resistance	Exciter stator winding resistance, DL6	25.0	ohms	at 77°F (25°C)
Resistance	Exciter stator winding resistance, DL6T	40.0	ohms	at 77°F (25°C)
Resistance	Generator rotor ground insulation	100,000	ohms	minimum
Resistance	Generator stator winding to laminations	less than 100,000	ohms	indicates questionable stator; Megger 500 VDC or more
Resistance	Governor actuator coil resistance	1 ±10%	ohms	at 77°F (25°C); resistance to case infinity
Resistance	Insulation resistance to ground	100,000 or greater	ohms	500 VDC or more megger; exciter stator/rotor and main rotor/stator
Resistance	Magnetic pickup DC resistance	175 ±15%	ohms	at 77°F (25°C); disconnected from terminals 5 and 6
Resistance	Magnetic pickup coil resistance	175 ±15%	ohms	at 77°F (25°C); leads to case infinity

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	Ethylene glycol antifreeze (permanent type) and clean water; 50/50 mixture				Use soft water; contains rust and corrosion inhibitor; no stop-leak additive. Capacities: DGAB 11.5 L (12.2 QT); DGAC/DGAD 16.8 L (17.8 QT); DGAE 17.5 L (18.5 QT).
Coolant	50/50 solution of ethylene glycol anti-freeze and water	Must contain rust and corrosion inhibitor, no stop-leak additive	above -37°C	9.4 L	50/50 mixture provides freeze protection to -34 F (-37 C); do not exceed 50/50; MDL3/MDL4 10 quarts (9.4 L), MDL6 3.3 gal (12.5 L). Use clean, low-mineral, distilled or soft water
Engine oil	15W-40, 30, 20W-20, 10W	API CD/SG, CD/SF or MIL-L-2104C		5.7 L	MDL3/MDL4 capacity 6 quarts (5.7 L); MDL6 capacity 9 quarts (8.5 L). 5W-20 or 5W-30 must be synthetic meeting MIL-L-46167, MIL-L-2104C or MIL-L-46152B; 5W-20/5W-30 mineral base oils not recommended
Engine oil	API CD/SF or CE/SF; multigrade	API CD/SF or CE/SF			Preferred oil grades per Table 5-2; choose grade for lowest expected temperature. Capacities: DGAB 5.7 L (6 QT); DGAC/DGAD 8.5 L (9 QT); DGAE 11.4 L (12 QT).
Engine oil	SAE 10W-30				RM92-8M0086220U6 / RM92-8M0086221U3
Engine oil	SAE 15W-40				RM92-8M0096794U3; diesel engines
Engine oil	SAE 25W-40				RM92-8M0086227U3 / RM92-8M0086224U3
Engine oil	TC-W3	TC-W3			2-cycle outboard oil; RM92-858026QB1U6 / RM92-858027QB1U3 / RM92-858037QB1U3
Fuel	ASTM 2-D (No. 2 Diesel) or ASTM 1-D (No. 1 Diesel)	Minimum Cetane number 45			Use No. 1 diesel when ambient temperatures are below 0°C (32°F) and during long periods of light load. Low sulfur; cloud point at least 10 degrees below lowest expected fuel temperature.
Gear oil	SAE 80W90				LUB11564U12 / LUB11565 / LUB11540U12 / LUB11552U12 / LUB11546
Gear oil	SAE 90W				RM92-858064QB1U6 / RM92-858065QB1U2
Grease	Lithium grease with Teflon				LUB11363
Grease	Marine grease				LUB11400 / LUB11406
Grease	Molykote				Apply a thin film of Molykote grease to mating surfaces of the end bearing and the end bearing hole.
Other	DOT 3				Trailer brake system; reservoir should be at least half full
Other	DOT-3 heavy duty hydraulic fluid				Trailer brake system bleeding
Other	Power Trim & Tilt fluid				LUB11591U12 / LUB11592 / LUB11593
Other	distilled water				Battery electrolyte; add distilled water to maintain proper level.

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
FAULT 1	Fault 1	Undedicated fault; may be programmed as shutdown or non-shutdown and as timed or non-timed; normally set for timed shutdown.		Investigate optional fault selection; contact dealer if needed.
FAULT 2	Fault 2	Undedicated fault; same features as Fault 1; normally set for non-timed shutdown.		Investigate optional fault selection; contact dealer if needed.
HI ENG TEMP	High engine temperature shutdown	Engine shut down because coolant temperature rose above 222°F (106°C) or coolant level is low.	Shutdown	Allow to cool; check coolant level, airflow, and fan belt; reset and restart; contact dealer if fault persists.
LO FUEL	Low fuel	Fuel supply marginally low.	Warning	Check fuel supply and replenish.
LO PRES	Low oil pressure shutdown	Engine shut down because oil pressure dropped below 14 psi (97 kPa).	Shutdown	Check oil level, lines, and filters; reset and restart; contact dealer if pressure is not 30 to 55 psi.
LOW ENG TEMP	Low engine temperature	Engine temperature marginally low for starting; indicates inoperative coolant heater. Lamp lights when engine coolant temperature is 70°F (21°C) or lower.	Warning	Check coolant heater power, fuse, cord, and coolant level; contact dealer if fault persists.
LOW OIL PRES	Low oil pressure shutdown	Red lamp indicates engine shutdown because of critically low oil pressure.	Shutdown	Check oil level and LOP switch; inspect engine.
OVERCRANK	Overcrank shutdown	Starter locked out because of excessive cranking time.	Shutdown	Check fuel system, fuel filter, and air filter; reset and restart; contact dealer if fault persists.
OVERSPEED	Overspeed shutdown	Engine shut down because of excessive speed.	Shutdown	Contact authorized dealer or distributor for service.
PRE HI ENG TEMP	Pre-high engine temperature	Engine temperature marginally high, 202°F (94°C).	Warning	Reduce load if possible, check airflow, and improve ventilation; if engine can be stopped follow high engine temperature procedure.
PRE HIGH ENG TEMP	Pre-high engine temperature	Yellow lamp indicates engine temperature is marginally high.	Warning	Find and correct cause.
PRE LO OIL PRES	Pre-low oil pressure	Oil pressure marginally low, 20 psi (137 kPa) or less.	Warning	Find and correct cause as soon as possible.
RUN	Run	All engine systems normal.	Info	No corrective action required.
SWITCH OFF	Switch off	Generator set is not in automatic start operation mode.	Warning	Move Run/Stop/Remote switch to REMOTE for automatic starting.

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

Procedures

Adjust magnetic pickup adjustment

Tools: Compressed air, Jam nut wrench

Rotate engine so ring gear tooth is centered in MPU hole.
Clean mounting hole with compressed air.
Turn MPU in until it contacts flywheel tooth directly below.
Turn out 1/2 turn and lock with jam nut.
Be sure pickup does not rotate when tightening jam nut.

Adjust voltage adjust potentiometer R21 adjustment

⚠ Contact with high voltage can cause severe personal injury or death.

Tools: Insulated screwdriver

Loosen locking nut of R21 and adjust to mid-range.
Start genset and bring temperature to normal.
With no load, turn Phase Selector to read output voltage and current.
Adjust R32 for approximate desired voltage.
Fine-adjust with R21 and tighten locking nut without changing setting.

Adjust voltage regulator adjustment

⚠ Use insulating mat or dry wood platform when control doors are open.

Tools: Insulated screwdriver, Accurate voltmeter

Open control panel doors and set S1, S2, and S3 per table.
Connect accurate voltmeter to TB1-2 and TB1-3 if no AC meter.
Start genset and bring temperature to normal.
Turn R32 to set no-load voltage.
Stop genset and close control panel doors.

Adjusting the Pump Belt Tension adjustment

⚠ Accidental starting of the generator set can cause severe personal injury or death; disconnect starting battery cables (negative first) before service.

Tools: belt tension tool

Remove battery cables (negative cable first) and remove belt guard.
Inspect belt for ply separation, fraying and glazing; replace if any condition exists.
Measure belt tension with a belt tension tool; should be 60 pounds (267 N).
Loosen bolt through elongated slot in sea water pump bracket and slide pump until proper tension is secured.
Reinstall belt guard; do not operate genset without belt guard in place.

Calibrate electronic governor adjustment

⚠ Keep hands and fingers clear while performing tests on operating equipment.

Tools: Tachometer or frequency meter

Check actuator linkage does not bind through full travel.
Attach tachometer or frequency meter.
Set GAIN adjustment to second mark from zero.
Disconnect governor rod from throttle lever.
Start genset and adjust right stop to 72 Hz for 60 Hz gensets.
Adjust left stop to take up slack and tighten locknut.
Stop, attach governor rod, start, and adjust SPEED to 60 or 50 Hz.
Connect load and adjust GAIN clockwise until stable.

Electronic governor adjustment/calibration adjustment

⚠ Contact with rotating machinery can cause severe personal injury or death.

Tools: Tachometer or frequency meter, Screwdriver

Check actuator linkage does not bind through full travel; ensure terminals 7 and 8 are jumpered.
Attach tachometer to engine or frequency meter to generator if control panel lacks one.
Set Controller GAIN adjustment to second mark from zero.
Disconnect governor rod from throttle lever.
Place Run/Stop/Remote switch in Run position to start genset.
Adjust right stop screw on mechanical governor to obtain 72 Hz (2160 r/min) for 60 Hz gensets or 62 Hz (1860 r/min) for 50 Hz gensets.
Adjust left stop screw to just take up slack, then tighten locknut without binding shaft.
Stop genset, attach governor rod to throttle lever, start, and adjust Controller SPEED screw for 60 Hz or 50 Hz.
Connect full rated load; if genset cannot manage load, shorten governor rod one-half turn and repeat; tighten locknuts.
Connect 1/4 rated load; turn GAIN screw clockwise until actuator hunts, then back off until stable.
Stop genset, wait 30 seconds for turbo coast down if equipped, restart, and check for speed overshoot.
Restart genset and check frequency and stability under various loads.
Stop genset and remove tachometer or frequency meter if attached.

Fan Belt Adjustment adjustment

Loosen alternator bolt passing through elongated slot in mounting bracket.
Slide alternator until fan belt tension is 60 lbs (267 N).
Tighten alternator mounting bolt to lock alternator in place.
Check tension and repeat if necessary.

Overspeed Switch Adjustment adjustment

Tools: Accurate tachometer or strobotach

Correct the speed range by turning the adjusting screw, thereby changing the magnetic air gap (Figure 5-3).
Check the overspeed trip point with an accurate tachometer or strobotach after adjustment.

Voltage Adjustment - Electronic Voltage Regulator adjustment

⚠ Do not adjust the other potentiometer (Volts/Hz Adjust); it is factory set using special calibration equipment.

With the generator set running, verify the set has stabilized and is running at correct speed (frequency).
Set the Voltage Adjust potentiometer on the regulator board assembly for correct voltage (Figure 4-12).

Voltage Adjustment - Transformer Voltage Regulator adjustment

⚠ Accidental starting of the set can cause severe personal injury or death. Disconnect the battery cables when repairs are made to the engine, controls, or generator.

Stop the generator set.
Change tap connections on the transformer T21 to adjust output voltage.
When replacement is necessary, install leads to the same terminals of the new transformer.
Refer to the model wiring diagram or the generator reconnection diagrams under Test (Q).

Voltage adjust potentiometer R21 adjustment

⚠ Contact with high voltage can cause severe personal injury or death.

Tools: Screwdriver

Loosen locking nut of R21 on control front panel and adjust R21 to mid-range.
Start genset and operate to bring temperature to normal.
With no load, turn Phase Selector switch to read output voltage/current.
Adjust R32 on voltage regulator for approximate desired voltage.
Fine-adjust voltage with R21; tighten locking nut carefully without changing setting.
Move Phase Selector switch to Off, stop genset, and set control for standby readiness.

Voltage regulator adjustment adjustment

⚠ Contact with high voltage can cause severe personal injury or death.

Tools: Insulated screwdriver, Accurate voltmeter

Open control panel doors and set S1, S2, S3 per correct stability range and mode.
With AC meter option use panel meter; without it connect accurate voltmeter to regulator TB1-2 and TB1-3.
Start genset and operate to bring temperature to normal.
Using insulated screwdriver, turn R32 potentiometer to increase or decrease no-load voltage to proper setting.
Stop genset, close control doors, and set control for operation readiness.

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
		VR21 jumper terminals 6 & 7 for 60 Hz	6, 7	Electronic voltage regulator wiring diagram
		VR21 jumper terminals 7 & 8 for 50 Hz	7, 8	Electronic voltage regulator wiring diagram
110 VAC	1	Transformer regulation, voltage codes 3C, 53C and 538		Move taps on T21 to adjust output voltage
110/190V, 115/220V, 120/208V, 127/220V	3	CODE 518 50HZ		Electronic regulation reconnection
110/220 VAC	1	Transformer regulation, voltage codes 3C, 53C and 538		Move taps on T21 to adjust output voltage
110/220V, 115/230V, 120/240V		CODE 518 50HZ		Electronic regulation reconnection
110/220V, 115/230V, 120/240V	1	CODE 518 50HZ, 1PH 3W		Electronic regulation reconnection
110V, 115V, 120V	1	CODE 518 50HZ, 1PH 2W		Electronic regulation reconnection
120 VAC	1	Transformer regulation, voltage codes 3C, 53C and 538		Move taps on T21 to adjust output voltage
120/208V, 127/220V, 139/240V	3	CODE 18 60HZ		Electronic regulation reconnection
120/240 VAC	1	Transformer regulation, voltage codes 3C, 53C and 538		Move taps on T21 to adjust output voltage
120/240V	1	CODE 18 60HZ		Electronic regulation reconnection
120/240V	1	CODE 18 60HZ, 1PH 3W		Electronic regulation reconnection
208 VAC		Switch S1 position 1	stator T7 and T8	Transformer TX1 primary H1-H3
220 VAC	1	Transformer regulation, voltage codes 3C, 53C and 538		Move taps on T21 to adjust output voltage
220/380V, 230/400V, 240/416V, 254/440V	3	CODE 518 50HZ		Electronic regulation reconnection
240 VAC		Switch S1 positions 2 and 3	stator T7 and T8	Transformer TX1 primary H3-H5
240 VAC	1	Transformer regulation, voltage codes 3C, 53C and 538		Move taps on T21 to adjust output voltage
240/416V, 254/440V, 277/480V	3	CODE 18 60HZ		Electronic regulation reconnection
240V	1	CODE 18 60HZ, 1PH 2W		Electronic regulation reconnection

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 oil capacity of the Cummins/Onan 6A3.4?

The Cummins/Onan 6A3.4 engine has an oil capacity of 8.5 liters.

Which generators use the Cummins/Onan 6A3.4 engine?

The Cummins/Onan 6A3.4 powers 3 generator set(s), including Cummins/Onan DGAC, Cummins/Onan DGAD, Cummins/Onan MDL6.

What is a common problem with the Cummins/Onan 6A3.4 engine?

A commonly reported issue on generators using the Cummins/Onan 6A3.4 is: No AC output voltage at rated engine RPM. Cause: Control panel field breaker CB21 off. Fix: Push to reset breaker; if voltage is unstable, high or low, or causes breaker to trip, see Flow Charts B, C, D or E.