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Kubota V2803B Engine

The Kubota V2803B is a 2.75 L 4-stroke cycle, indirect injection, water cooled diesel engine rated at 1800 rpm. It powers generator sets from Cummins/Onan, including the MDKAF and MDKB. It holds 12 L (3.2 gal) of oil and 7.6 L (2.0 gal) of coolant.

Also known as: Kubota V2803B

2.748 L

Displacement

1800 rpm

Rated speed

12.0 L

Oil capacity

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

Engine specifications

Oil capacity	12.0 L
Coolant capacity	7.6 L
Displacement	2.748 L
Aspiration	4-Stroke Cycle, Indirect Injection, Water Cooled Diesel
Rated speed	1800 rpm

Generator sets powered by this engine

Cummins/Onan MDKAF Cummins/Onan MDKB

How to read your Kubota engine serial & model number →

Common problems

Engine cranks but does not start
Cause: Fuel is not getting to the engine
Fix: Check fuel pump per Checkout H (Section 3); Place meter on fuel pump terminal and press Start switch: is voltage reaching fuel pump?; Test fuel tank level, shutoff valves, fuel lines and connections, fuel filters, injection pump; Air in fuel lines: prime fuel system
Starter engages-disengages (battery voltage dips below 6 volts while cranking—low battery charge, poor connections, long cables)
Cause: Battery voltage dips below 6 volts while cranking—low battery charge, poor connections, long cables
Fix: Clean and tighten the positive (+) and negative (-) battery cable connections at the battery and genset (Page 3-6); Recharge or replace the battery. Refer to the battery manufacturer's recommendations; Increase battery cable size or run parallel cables
Low oil pressure Low oil pressure-CODE NO. 2
Fix: Check the engine oil level and add or drain oil as necessary (p. 4-3). Repair any oil leaks.
Unstable voltage, engine speed stable
Cause: Broken wires or loose connections on voltage regulator assembly
Fix: Check wiring harness from regulator assembly to end bell per TEST [J]. Check OK? Yes: Replace the voltage regulator per procedure (D). No: Repair as required. Repair wiring or replace as required.
No AC output voltage at rated engine RPM
Cause: Load circuit breakers not closed
Fix: Close circuit breakers, or replace if bad. If voltage is unstable, high or low, or causes breaker to trip, see Flow Charts B or C.
Engine does not crank
Cause: Open circuit breaker CB1, CB2 or CB4
Fix: Check to see if breaker is accidentally tripped; Check and correct fault conditions that might trip breakers: CB1: check shorts to ground on/near glow plug circuits; CB2: check and correct fault conditions sensed by engine fault sensors: S2: high engine temperature, S3: low coolant level, S4: low oil pressure, S5: high exhaust temperature; CB2: check possible shorted fault sensors S1, S2, S3, S4; CB4: check K7 stop solenoid for adjustment
UNDERVOLTAGE 13
Fix: Reduce the number of connected appliances, especially when air conditioners and battery chargers are running.
OVERVOLTAGE 12
Fix: See an authorized Onan dealer.
OVERCRANK 4
Fix: 1. Check the fuel tank and fill as necessary. (Note: The arrangement of pickup tubes in the fuel supply tank probably is such that the genset will run out of fuel before the propulsion engines.) 2. Open any closed fuel valves. 3. Remove any blockage in the combustion air inlet (front grille) or exhaust system. 4. Tighten loose fuel line fittings so that air cannot be drawn in by genset lift pump suction. 5. Drain and/or replace the fuel filter (Page 16) and prime the fuel system (Page 8). 6. Drain and/or replace fuel supply system filters and prime the fuel system (Page 8).
LOSS OF RAW WATER FLOW 7
Fix: 1. Open the sea cock. 2. Close the sea cock and clean the sea water strainer. If the strainer is above the water line, fill it with water to assist priming. Secure the strainer cover and reopen the sea cock. 3. Reconnect or replace any disconnected or leaking raw water hoses (Page 19). 4. Remove any blockage from the strainer on the through-hull fitting on the bottom side of the hull. 5. Replace the raw water impeller (Page 23).
HIGH ENGINE TEMPERATURE 1
Fix: 1. Add coolant as necessary and repair leaks (Page 18). 2. Replace the engine thermostat, which might not be opening fully (Page 21). 3. Clean the raw water tubes in the heat exchanger, which might be clogged with scale (Page 22). 4. Flush the coolant system to remove coolant passage fouling (Page 18).
Actuator Overload 22
Cause: Load; Fuel supply; Intake restriction; Governor actuator operation
Fix: Check: Load; Fuel supply; Intake restriction; Governor actuator operation
“Check Engine” Fault Shutdown
Cause: Low engine oil pressure
Fix: Check engine oil level, repair any leaks and fill to the proper level (p. 18).
Engine starts but stops after several seconds
Cause: Fault conditions cause fault breaker CB2 to open
Fix: CB2: check and correct fault conditions sensed by engine fault sensors: S2: high engine temperature: check water pump operation; S3: low coolant level; S4: low oil pressure; S5: high exhaust temperature; Check possible overspeed conditions; Engine speed set too high: reset to 1500 or 1800 rpm according to instructions in Section 4 of manual; Voltage regulator board 50/60 Hz switch is set at 50 Hz while governor lever is set at 60 Hz: both settings must be the same; Check all B+ wiring for shorts to ground
Engine does not crank from remote panel
Cause: Emergency Stop Switch OFF
Fix: Push ON.

Compiled from service & troubleshooting documentation across every generator set that uses the Kubota V2803B.

Service intervals

Item	Action	Hours	Months	Notes
Check Engine Oil Level	Check	8 hr
Coolant Level	Check	8 hr		Before first startup of each day.
Drain Water from Fuel Filter	Drain	8 hr
Engine oil level	Check	8 hr		Every Day/8 Hrs (Table 4-1)
Exhaust system	Check	8 hr
Exhaust system	Inspect	8 hr		Look over entire exhaust system and listen for leaks every startup and after every eight hours of operation
Fuel Filter	Drain	8 hr
Fuel Filter Water	Drain	8 hr
Fuel level	Check	8 hr
General Inspection	Check	8 hr		Daily, 8-Hr; includes Oil Level, Coolant Level, Fuel System, Exhaust System, Battery, and Sea Water Strainer Checks.
General Inspection	Inspect	8 hr		Includes inspection of oil level, coolant level, fuel system, exhaust system, batteries and battery connections; before first start of day and after every 8 hours
General Inspection (Oil Level, Coolant Level, Fuel System, Exhaust System, Battery, Sea Water Strainer)	Check	8 hr		Every day, all models (MDKBH, MDKBJ, MDKBW, MDKB & MDKD, MDDCX)
General Inspection (oil, coolant, fuel, exhaust, batteries)	Inspect	8 hr		every day / before first start of the day
Generator Set	Inspect	8 hr		General Inspection; includes oil level, coolant level, fuel system, exhaust system, batteries and sea water strainer.
Genset	Inspect	8 hr		Check for oil, fuel, coolant and exhaust system leaks
Oil level	Check	8 hr
Sea Water Strainer	Clean	8 hr		Clean if necessary and make sure sea cock is open.
Change Engine Oil and Oil Filter - All except MDKBT & MDKBU	Change	50 hr		First service — after first 50 hrs, then every 200 hrs/year
Change Engine Oil and Oil Filter - Only MDKBT & MDKBU	Change	50 hr		First service — after first 50 hrs, then every 200 hrs/year
Engine Oil and Oil Filter (All except MDKBT & MDKBU) - after first 50 hours	Change	50 hr		First service — Break-in oil change; also change the oil and oil filter after the first 50 hours of operation on a new or re-built engine.
Engine Oil and Oil Filter (Only MDKBT & MDKBU) - after first 50 hours	Change	50 hr		First service
Engine oil and oil filter - all except MDKBT & MDKBU	Change	50 hr		First service — After first 50 hours of operation; then per Table 4-1
Engine oil and oil filter - only MDKBT & MDKBU	Change	50 hr		First service — After first 50 hours of operation; then per Table 4-1
Battery	Check	100 hr	1 mo	See battery manufacturer's recommendations.
Battery and Battery Connections	Inspect	100 hr	1 mo	See battery manufacturer's recommendations.
Check V-Belt Tension	Check	100 hr		check for slippage, cracking and wear
Engine Oil and Oil Filter (All except MDKBT & MDKBU)	Change	100 hr	1 mo	First service — Perform twice as often when using high sulfur fuel.
Fuel Filters	Drain	100 hr	1 mo	Every Month / 100 Hrs
Genset	Clean	100 hr	1 mo	Do not clean while running
Inspect Battery and Battery Connections	Inspect	100 hr		monthly
Siphon Break	Check	500 hr	12 mo	Monthly, 100-Hr
Siphon Break	Inspect	100 hr	1 mo	Every Month / 100 Hrs
Water from Fuel Filter	Drain	100 hr	1 mo	Every Month/100 Hrs
Water in Fuel	Drain	100 hr	1 mo	Every Month/100 Hrs; drain more often if fuel quality is poor or condensation cannot be avoided
Water in Fuel Filter	Drain	100 hr		Every Month / 100 Hrs
Zinc Anode	Inspect	500 hr	1 mo	Replace as recommended.
Zinc Anode	Replace	500 hr	12 mo	Monthly, 100-Hr; Model MDKAU does not have a zinc anode to replace.
Brushes & Slip Rings	Check	200 hr		Yearly, 200 Hrs (MDKBH, MDKBJ, MDKBW only); must be performed by trained mechanic; not applicable to other listed models (—)
Engine Oil and Oil Filter	Change	200 hr	12 mo	First service — Every Year/200 Hrs
Engine Oil and Oil Filter (Only MDKBT & MDKBU)	Change	200 hr	12 mo	First service — Perform twice as often when using high sulfur fuel.

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	Exhaust piping minimum clearance from combustible construction	9	inches (229 mm)
Clearance	Minimum clearance, non-service sides	2	inches (51 mm)
Clearance	Raw water pump shaft grooving depth	.015	in	exceeding requires pump replacement
Clearance	Sound shield end clearance for air flow	1	inches (25 mm)
Clearance	Sound shield top clearance to open service door latches	2	inches (51 mm)
Clearance	V-Belt Tension Deflection	0.4	inch (10 mm) @ 20 lbs (10 kg)
Clearance	V-belt deflection	0.4 inch (10 mm)	inch (mm)	20 lbs (10 kg) applied to middle of pulley span
Clearance	V-belt deflection	3/8	inch (10 mm) at 20 lbs (10 kg) applied
Clearance	V-belt deflection at 20 lbs (10 kg)	3/8 inch (10 mm)	in (mm)	tension check at middle of pulley span
Clearance	V-belt deflection at middle of pulley span	3/8 inch (10 mm)		with 20 lbs (10 kg) applied
Clearance	Valve Lash (cold) - D1105/V1505/V2003M/V2403M	0.0071-0.0087	in (0.18-0.22 mm)	cold
Clearance	Valve Lash (cold) - V3300-E2B	0.009-0.010	in (0.23-0.27 mm)	cold
Compression	Compression Ratio (MDKAV/MDKAW/MDKAZ)	22:1
Compression	Compression Ratio (MDKBD/MDKBE/MDKBF)	23:1
Gap	V-belt deflection	0.4	inch (10 mm)	20 lbs (10 kg) applied to middle of pulley span
Injection timing	Fuel Injection Timing	12 deg BTDC	deg BTDC
Injection timing	Fuel Injection Timing	13.5-15 deg BTDC	deg BTDC
Injection timing	Fuel Injection Timing	14.25-15.75 deg BTDC	deg BTDC
Injection timing	Fuel Injection Timing	14.75-16.25 deg BTDC	deg BTDC
Injection timing	Fuel Injection Timing	15.5 - 17.5	° BTDC
Injection timing	Fuel Injection Timing	18.25 − 19.75	° BTDC
Injection timing	Fuel Injection Timing	18° – 20°	BTDC
Injection timing	Fuel Injection Timing - D1105	14.75-16.25	° BTDC
Injection timing	Fuel Injection Timing - V1505	14.25-15.75	° BTDC
Injection timing	Fuel Injection Timing - V2003M	13.5-15	° BTDC
Injection timing	Fuel Injection Timing - V2403M	13.5-15	° BTDC
Injection timing	Fuel Injection Timing - V3300-E2B	12	° BTDC
Injection timing	Fuel injection timing	12	degrees BTDC
Injection timing	Fuel injection timing	14.5	degrees BTDC
Injection timing	Fuel injection timing	15.5 - 17.5 degrees BTDC	degrees BTDC
Injection timing	Fuel injection timing	16	degrees BTDC
Injection timing	Fuel injection timing	16.5	degrees BTDC
Injection timing	Fuel injection timing	18 - 20	degrees BTDC	timing marks line up at 19 degrees BTDC
Other	Battery Charging Output	Trickle (3 amps)
Other	Battery cable gauge	1	AWG	total cable length 22 ft (6.7 m); approx. diameter 9.43 mm
Other	Battery cable gauge	1/0	AWG	total cable length 30 ft (9.1 m); approx. diameter 9.46 mm
Other	Battery cable gauge	2	AWG	total cable length 18 ft (5.5 m); approx. diameter 7.42 mm
Other	Battery cable gauge	3	AWG	total cable length 14 ft (4.3 m); approx. diameter 6.61 mm
Other	Battery cable gauge	4	AWG	total cable length 10 ft (3 m); approx. diameter 5.88 mm
Other	Combustion Air	18 CFM (30 M3/HR)
Other	Compression Ratio	22.8:1
Other	Compression Ratio	23.5:1
Other	Compression Ratio	24.3:1
Other	Compression Ratio	24:1
Other	Compression ratio	22.5:1
Other	Compression ratio	22:1
Other	Compression ratio	23:1
Other	Coolant Capacity	2.2 quart (2.1 liter)
Other	Coolant Flow	3.0 gpm (16 liter/min)		50 Hz
Other	Coolant Flow	3.5 gpm (13 liter/min)		60 Hz
Other	Engine Oil Capacity	2.2 quart (2.1 liter)
Other	Firing Order (Clockwise Rotation)	1-2
Other	Firing order (clockwise rotation)	1-2-3
Other	Firing order (clockwise rotation)	1-2-4-3
Other	Firing order (clockwise rotation)	1-3-4-2
Other	Firing order (clockwise rotation)	1-3-5-4-2
Other	Fuel Injection Order (Firing Order, clockwise rotation)	1-2
Other	Fuel pump delivery (test)	2/3	liter per minute	prime test, 1 liter container
Other	Fuel pump delivery rate	2/3 liter per minute (1 liter in 1-1/2 minutes)	liter/min	prime mode
Other	Generator Cooling Air	60-80 CFM (100-135 M3/HR)

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	50/50 solution of ethylene glycol or propylene glycol antifreeze and clean water				Antifreeze should include a rust inhibitor but not a stop-leak. Change coolant every year. Fill recovery tank half way between hot and cold marks.
Coolant	50/50 water/ethylene glycol			2.1 L	MDKBH; also stated as 2.2 Qt
Coolant	Fleetguard ES Compleat / EG Premix antifreeze (ethylene glycol based)				Purple coloured viscous liquid; boiling point 107 C, flash point 121 C.
Coolant	Fleetguard ES Compleat and EG Premix (ethylene glycol based)
Coolant	50/50 ethylene glycol/water	ASTM D5345 (prediluted) or ASTM D4985 (concentrated, 40-60% quality water)	above -37°C		Protects to -34°F (-37°C)
Coolant	50/50 ethylene glycol/water mixture	Fully formulated with rust inhibitors and coolant stabilizers	above -37°C	5.0 liter	MDKAW, MDKAZ
Coolant	50/50 mixture of water and ethylene glycol		above -37°C	2.1 liter	Use best quality ethylene glycol antifreeze with rust inhibitors and coolant stabilizers; distilled water best. Protection down to -34°F (-37°C).
Coolant	50/50 mixture of water and ethylene glycol (best quality)	Fully formulated with rust inhibitors and coolant stabilizers; not with stop-leak additives; use distilled water	above -37°C	7.6 L	Good for -34° F (-37° C); ethylene glycol antifreeze is considered toxic
Coolant	50/50 mixture of water and ethylene glycol antifreeze	Fully formulated with rust inhibitors and coolant stabilizers; use low-mineral fresh water (distilled best)	above -37°C	4.0 liter	MDKAV, MDKBG; mixture good for -34 F (-37 C)
Coolant	50/50 mixture of water and ethylene glycol antifreeze, fully formulated with rust inhibitors and coolant stabilizers	ASTM D5345 for 50/50 prediluted coolant or ASTM D4985 for concentrated coolant with 40% to 60% quality water	above -37°C		50/50 mixture gives protection from freezing down to -34 F (-37 C); use fresh water low in minerals and corrosive chemicals (distilled best)
Coolant	Ethylene glycol antifreeze, 50/50 mixture of water and ethylene glycol	ASTM D5345 for 50/50 prediluted coolant or ASTM D4985 for concentrated coolant with 40% to 60% quality water	above -37°C		Provides protection from freezing down to -34 F (-37 C). Use fresh water low in minerals; distilled water is best. Fully formulated with rust inhibitors and coolant stabilizers.
Coolant	Ethylene glycol antifreeze, fully formulated with rust inhibitors and coolant stabilizers; 50/50 mixture of water and ethylene glycol		above -37°C	2.1 liter	Protection from freezing down to -34°F (-37°C); use fresh water low in minerals, distilled best
Coolant	ethylene glycol antifreeze, 50/50 mixture with water		above -37°C		Good to -34F (-37C)
Coolant	ethylene glycol antifreeze, 50/50 mixture with water for freeze protection to -34°F (-37°C)	ASTM D5345 (50/50 prediluted) or ASTM D4985 (concentrated, 40-60% quality water)	above 37°C		distilled water best
Engine oil	15W40			2.1 L	MDKBH; also stated as 2.2 Qt. Shipped with 15W40 engine oil.
Engine oil	API CH-4 or better, SAE 15W-40 recommended year-round	API/SAE			Synthetic motor oil not recommended
Engine oil	API Service Category CI-4 or better; SAE 15W-40 recommended	API CI-4		2.1 liter	2.2 quart (2.1 liter). Multigrade oils such as SAE 15W-40 are recommended for year-round use.
Engine oil	API Service Category CI-4 or better; SAE 15W-40 recommended year-round	API			choose viscosity per Figure 3-1 ambient chart
Engine oil	Multigrade oils such as SAE 15W-40 recommended for year-round use; choose SAE viscosity grade per ambient temperature (Figure 3-1)	API Service Category CI-4 or better			4.0 L for MDKBK/MDKBL; 4.3 L for MDKBM/MDKBN; 7.6 L for MDKBP/MDKBR; 12 L for MDKBS; 10.4 L for MDKBT/MDKBU
Engine oil	Premium Blue E 15W40			2.1 L (2.2 qt)	Lubricant oil - Premium Blue E 15W40
Engine oil	SAE 10W-30				RM92-8M0086220U6 / RM92-8M0086221U3
Engine oil	SAE 15W-40	API Class CH-4 or better		4.3 liter	MDKAW, MDKAZ
Engine oil	SAE 15W-40 (multi-grade recommended for year-round use)	API Class CG-4, CF-4, CF or better		7.6 L (MDKAD, MDKAE)	Choose viscosity grade per Figure 2 for ambient temperature range; MDKAF capacity 13 qt (12 L)
Engine oil	SAE 15W-40 (multi-grade recommended for year-round use; choose viscosity grade per ambient temperature)	API Performance Class CH-4 or better		4.0 liter	MDKAV, MDKBG; synthetic motor oil not recommended
Engine oil	SAE 15W-40 (multigrade recommended for year-round use); choose viscosity grade for ambient temperature (Figure 3-1)	API Service Category CI-4 or better
Engine oil	SAE 15W-40 (multigrade) recommended for year-round use	API Service Category CI-4 or better		2.1 liter	Choose viscosity grade appropriate for ambient temperatures expected until next scheduled oil change
Engine oil	SAE 15W-40 multi-grade recommended for year-round use	API Service Category CI-4 or better		2.1 liter	Choose viscosity grade appropriate for ambient temperatures expected until the next scheduled oil change (Figure 3-1)
Engine oil	SAE 15W-40 multigrade recommended; choose viscosity grade per ambient temperature (Figure 3-1)	API Service Category CI-4 or better			Lube oil capacity: 4.2 quart (4.0 liter) MDKBK/MDKBL; 4.5 quart (4.3 liter) MDKBM/MDKBN; 8 quart (7.6 liter) MDKBP/MDKBR; 12.7 quart (12 liter) MDKBS; 11 quart (10.4 liter) MDKBT/MDKBU. Add 1 quart (0.9 liter) when level falls to ADD mark.
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

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
1	High Engine Temperature	Engine coolant temperature exceeded design limit	Shutdown	Add coolant, repair leaks, replace thermostat, clean raw water tubes, flush coolant system
2	Low Oil Pressure	Low oil pressure	Shutdown	Add engine oil or drain excess oil
3	Service Check	Indicates presence of second-level shutdown	Shutdown	Check second-level shutdown code by pressing STOP once
4	Overcrank	Cranking exceeded 20 to 60 seconds without start	Shutdown	Check fuel tank, open valves, remove blockage, tighten fittings, replace fuel filter, prime
5	Warning - Shutdown due to Vessel CO	Dangerous levels of Carbon Monoxide in vessel	Shutdown	Get everyone out into fresh air immediately and seek medical attention
7	Loss of Raw Water Flow	Low raw water pressure in heat exchanger	Shutdown	Open sea cock, clean strainer, reconnect hoses, replace impeller
12	Overvoltage	Controller unable to maintain rated voltage	Shutdown	See an authorized Onan dealer
13	Undervoltage	Controller unable to maintain rated voltage	Shutdown	Reduce number of connected appliances
14	Overfrequency	Engine governor unable to maintain rated frequency	Shutdown	Reset breaker after starting, tighten fuel fittings, prime fuel system
15	Underfrequency	Engine governor unable to maintain rated frequency	Shutdown	Reduce appliances, check fuel, remove blockage, tighten fittings, prime
17	Over-Prime	Prime mode exceeded 5 minutes	Shutdown	Remove object holding control switch in prime position
22	Governor Overload	Maximum allowable time at full-duty cycle exceeded	Shutdown	Reduce appliances, check fuel, remove blockage, tighten fittings, prime
23	Faulty Oil Pressure Sender	Controller sensed grounded sender	Shutdown	See an authorized Onan dealer
24	Faulty Temperature Sender	Controller sensed open sender	Shutdown	See an authorized Onan dealer
27	Loss of Voltage Sense	Controller unable to sense output voltage	Shutdown	See an authorized Onan dealer
29	High Battery Voltage	Battery system at more than 19.2V (12VDC) or 38.4V (24V)	Shutdown	Check battery bank connections, select lower boost charge rate
32	STARTING FAULT	Controller could not detect cranking speed (quadrature zero crossings) for 3 seconds	Shutdown	De-energize PTO, run propulsion engines while starting, service battery connections, change oil viscosity, check starter relay K4, check wiring, service starter motor, service engine, replace controller
35	Control Card Failure	Microprocessor EEPROM error during self-test	Shutdown	See an authorized Onan dealer
36	Engine Stopped	Engine stopped without command by controller	Shutdown	Open fuel valves, check fuel tank, check mechanical damage, remove blockage, prime
37	Invalid Genset Configuration	Controller cannot determine genset operating parameters	Shutdown	See an authorized Onan dealer
38	Field Overload	High field voltage induced by high rotor temperature or low power factor loads	Shutdown	Remove blockages to generator airflow, reduce appliances
41	Grounded Rotor	F+ grounded	Shutdown	See an authorized Onan dealer
42	Processor Failure	Microprocessor ROM error during self-test	Shutdown	See an authorized Onan dealer
43	Processor Failure	Microprocessor RAM error during self-test	Shutdown	See an authorized Onan dealer
45	SPEED SENSE LOST	After start disconnect, controller lost speed sense (quadrature zero crossings) for 0.25 seconds	Shutdown	Check for open/shorted field (P3-7 to P3-8) and quadrature (P3-4 to P3-5) windings, service generator, replace controller
46	Genset Overload	The genset Controller shutdown the genset because engine load exceeded 135 percent of genset rating for 10 seconds	Shutdown	Reduce the number of loads on the genset.
48	Processor Failure	Controller unable to sense field voltage	Shutdown	See an authorized Onan dealer
57	OVERPRIME	A local or remote control switch was held in the Prime position for more than 5 minutes	Shutdown	Remove object holding switch in prime position, replace faulty control switch
58	High Exhaust Temperature	Exhaust temperature exceeded design limits	Shutdown	Reconnect/replace raw water hoses, replace impeller
59	Low Coolant Level	Coolant level low	Shutdown	Add coolant, repair leaks
61	Emergency Shutdown	Genset was shut down by fire suppression system or other external control	Shutdown	Make necessary repairs and reset external control
Code No. 5	Warning - Shutdown due to Vessel CO	Shutdown occurring due to the vessel CO detector	Warning	All status indicator lights in the control circuit will also blink the fault code. See Troubleshooting Chapter of the Operator Manual.
Code No. 61	Emergency Shutdown	Shutdown occurring due to external emergency shutdown device	Shutdown	All status indicator lights in the control circuit will also blink the fault code. See Troubleshooting Chapter of the Operator 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

Adjusting Frequency adjustment

Tools: Screwdriver

Remove access cover on left end of genset.
Find leads marked J8 HZ, 60 HZ and 50 HZ in wiring harness.
Connect 60 HZ or 50 HZ lead to J8 HZ as appropriate.
Secure access cover with four screws.

Adjusting High-Idle Speed adjustment

⚠ Keep your hands away from the engine belt and pulleys.

⚠ The actuator could overheat if the battery is left on more than 10 minutes.

⚠ Be prepared to clamp off supply and return fuel lines to stop the engine.

Tools: strobe or injector clamp-on tachometer, 12 volt battery, battery switch

Adjust the speed control lever stop.
Measure engine speed with a strobe or injector clamp-on type tachometer.
Remove the front and top access doors and loosen the front/left side panel assembly for access to the speed adjusting screw.
Disconnect the actuator leads and connect a 12 volt battery to the actuator terminals using a battery switch.
Switch the battery on, start the genset, measure engine speed (rpm) and stop the engine by switching off the battery.
Loosen the lock nuts on the two bottom screws and back out the clamping screw if speed is not between 3300 and 3400 rpm.
To increase speed turn the speed adjusting screw in 1 turn clockwise; to decrease turn it out 1 turn counterclockwise.
Repeat until high-idle speed is between 3300 and 3400 rpm and set the lock nut.
Run the clamping screw in by hand until snug, back it out 1-1/2 turns and set the lock nut.

Adjusting Speed Control Lever Stop adjustment

⚠ Accidental or remote starting can cause severe personal injury; disconnect the negative battery cable.

Remove the front and top access doors and loosen the front/left side panel assembly so it can swing left.
Loosen the stop screw locknut and back the screw out a few turns.
Turn the stop screw in until it just makes contact and set the locknut.

Adjusting V-Belt Tension adjustment

⚠ Accidental or remote starting can cause severe personal injury or death.

Disconnect the negative cable at the battery.
Remove the belt guard or enclosure top panel and access doors.
Loosen the alternator pivot bolt first, then the adjusting bracket bolt on top.
Pivot the alternator out to tighten belt tension.
Check tension by applying 20 pounds (10 kg) to the middle of the pulley span.
Tighten alternator bolts when deflection is 3/8 inch (10 mm), secure guard and reconnect cables, negative last.

Adjusting Valve Lash adjustment

⚠ Do not use the fuel injection timing marks when adjusting valve lash.

Rotate the engine clockwise (looking from the front) until the intake valve push rod just stops moving down (valve closed).
Turn the engine one half turn more.
Adjust lash for both intake and exhaust valves of that cylinder.
Repeat this procedure for the other cylinder.

Adjusting Voltage adjustment

⚠ Hazardous voltage; touching live parts can cause severe personal injury or death

Tools: Accurate AC voltmeter and frequency meter

Disconnect all generator loads and connect accurate AC volt and frequency meters.
Start genset and let voltage and frequency stabilize 5 to 10 seconds.
Rapidly press control switch to START 6 times within 10 seconds.
Amber lamp blinks once per second to confirm voltage set mode.
To raise voltage, press START and release quickly (about 0.6 volt per step).
To lower voltage, press START and release in approximately 2 seconds.
Normal operation resumes 20 seconds after last adjustment.

Adjusting Voltage Using Control Switch adjustment

Tools: separate voltmeter

Start the genset and let voltage and frequency stabilize for 5 to 10 seconds with all loads disconnected.
Rapidly press START 6 times during the first minute after startup to enter voltage adjust mode.
To adjust voltage up, press and quickly release START (about 0.6 volts per press).
To adjust voltage down, press and hold START for about 2 seconds (about 0.6 volts each press).
Wait about 20 seconds for the amber lamp to stop blinking, then press STOP to save the adjustment.
Restart the genset and check voltage.

Adjusting Voltage Using Digital Display adjustment

Start generator set and let voltage and frequency stabilize 5 to 10 seconds; disconnect all loads.
Rapidly press START 6 times during the first minute after startup to enter voltage adjust mode.
Press and quickly release START to increase voltage approximately 0.6 volts per press.
Press and hold START about 1 second to adjust voltage down.
Wait about 20 seconds for status to change from Volt Adj to Running, then press STOP to save.
Restart the generator set and check voltage; recalibrate AC voltage on the digital display.

Adjusting Voltage Using Optional Digital Display adjustment

Tools: Separate voltmeter

Start the genset and let voltage and frequency stabilize for 5 to 10 seconds; make sure all loads have been disconnected.
Rapidly press START 6 times during the first minute after startup to put the genset controller into voltage adjust mode.
To adjust voltage up, press and quickly release START; voltage increases approximately 0.6 volts each press and release.
To adjust voltage down, press and hold START for about 1 second; voltage decreases approximately 0.6 volts each press and release.
Wait about 20 seconds for the Display to indicate a Status change from Volt Adj to Running, then press STOP to stop the genset and save the adjustment.
Restart the genset and check voltage.
Recalibrate AC Voltage on the Digital Display as instructed in the Operator's Manual.

Changing Frequency adjustment

The genset control box has jumper leads marked HZ SEL and 60 HZ.
Connect for 60 HZ; disconnect for 50 HZ.
Apply the appropriate reconfiguration label over the 'As Manufactured' block on the nameplate.

Changing Generator Set Frequency adjustment

⚠ When changing frequency, make sure the line circuit breakers are suitable for the new output.

Remove the control box cover.
Connect J5 to P6 for 60 Hz.
Disconnect J5 from P7 for 50 Hz.
Apply the appropriate reconfiguration label.
Replace the control box cover.
Check and adjust voltage as necessary after the frequency has been changed.

Changing Genset Frequency adjustment

⚠ Incorrect electrical connections/adjustments can cause equipment damage, severe injury or death. Turn off genset and disconnect battery before adjustments.

Tools: Digital volt-ohmmeter, Frequency meter, Small flat-blade screwdriver

Identify new frequency and voltage.
Replace AC output circuit breaker if necessary for new load.
Move 60 Hz/50 Hz switch on regulator board to desired value.
Readjust engine speed for new frequency: 50 Hz 1500 RPM, 60 Hz 1800 RPM under no-load and full-load.
Apply maximum rated load and adjust frequency fine adjust screw to desired frequency.
Remove load and check no-load frequency is within 3 Hz of full-load frequency.
Tighten lock nut.

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
		50 Hz: Disconnect J5 from P7	J5, P6, P7	Frequency selection jumper leads in the genset control box
		60 Hz: Connect J5 to P6	J5, P6, P7	Frequency selection jumper leads in the genset control box
		HZ SEL / 60 HZ jumper leads in the control box	HZ SEL, 60 HZ	Connect for 60 Hz; disconnect for 50 Hz. Apply the appropriate reconfiguration label. Generator reconnection per schematic on Page A-2.
220/208	3	12 Lead Reconnectable		Applies to MDKDP (60 Hz), MDKDR (60 Hz), MDKDS
220/380	3	12 Lead Reconnectable		Applies to MDKDP, MDKDR, MDKDT, MDKDU
3-phase	3	12 Lead Reconnectable		Applies to MDDCW, MDDCU, MDDCY, MDDCS, MDDCT

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

Also used in

Reform-Werke 560 — Tractor

Other equipment known to use this engine, via filter-application cross-reference — useful for sourcing parts even when your exact machine isn't listed elsewhere on this page.

Common questions

What is the oil capacity of the Kubota V2803B?

The Kubota V2803B engine has an oil capacity of 12.0 liters.

What is the displacement of the Kubota V2803B?

The Kubota V2803B has a displacement of 2.748 liters.

Which generators use the Kubota V2803B engine?

The Kubota V2803B powers 2 generator set(s), including Cummins/Onan MDKAF, Cummins/Onan MDKB.

What is a common problem with the Kubota V2803B engine?

A commonly reported issue on generators using the Kubota V2803B is: Engine cranks but does not start. Cause: Fuel is not getting to the engine. Fix: Check fuel pump per Checkout H (Section 3); Place meter on fuel pump terminal and press Start switch: is voltage reaching fuel pump?; Test fuel tank level, shutoff valves, fuel lines and connections, fuel filters, injection pump; Air in fuel lines: prime fuel system.