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Cummins/Onan EM (SN5782U1G2RA) Engine

The Cummins/Onan EM (SN5782U1G2RA) is a 0.78 L 2-cylinder engine rated at 1800 rpm. It powers generator sets from Cummins/Onan, including the 4000. It holds 3.3 L (0.9 gal) of oil.

Also known as: Onan EM (SN5782U1G2RA)

0.782 L

Displacement

Cylinders

1800 rpm

Rated speed

3.3 L

Oil capacity

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

Engine specifications

Oil capacity	3.3 L
Displacement	0.782 L
Cylinders	2
Rated speed	1800 rpm

Generator sets powered by this engine

Cummins/Onan 4000

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

Common problems

Engine Does Not Crank
Cause: If engine cranks at set but not at remote control panel, fault is due to PC board P2/J2 connection not secure
Fix: Ensure that wiring harness jack connections are fully seated to PC board
Engine Starts But Stops When Start Switch is Released
Cause: Low oil pressure switch S2 not closing due to low oil level
Fix: Check oil level and add oil if low
Engine Lacks Power
Cause: Faulty ignition due to incorrect ignition timing
Fix: Adjust breaker point gap
Engine Misfires
Cause: Faulty ignition due to worn or fouled spark plugs
Fix: Replace spark plugs
Engine Surges
Cause: Sticking or binding (mechanical) governor linkage
Fix: Clean governor linkage (remove dirt or ice buildup). Check that linkage does not touch other parts.
Engine Cranks But Does Not Start
Cause: Faulty ignition due to worn or fouled spark plugs, worn ignition points, incorrect ignition timing, faulty plug wires, faulty condenser, or faulty electronic module
Fix: Refer to Ignition System (Section 6) for test and service procedures
Engine Overheats
Cause: Restricted airflow due to dirt or debris blocking air inlet or outlet
Fix: Clear away any debris that may restrict airflow to set; Do not use compartment for storage area
Low Oil Pressure
Cause: Oil viscosity too light or oil is diluted
Fix: Drain oil and refill with correct viscosity oil
Engine Hunts or Surges
Cause: Sticking or binding governor linkage
Fix: Clean and lubricate governor linkage
REMOTE CONTROL (if equipped) Run Lamp, Time Meter, or Battery Condition Meter Does Not Operate
Cause: Open circuit between control board A1 terminal 6 or 5 of remote connector plug P2/J2 and terminal 6 or 5 on start-stop switch S2
Fix: Check for continuity and correct if circuit is open
Engine Backfires
Cause: Faulty ignition due to incorrect ignition timing
Fix: Adjust breaker point gap
No AC output voltage
Cause: Open circuit breaker
Fix: Locate cause of overload and correct as required. Reset breaker.
AC Output Voltage Too Low or Too High
Cause: Engine governor incorrectly adjusted
Fix: Refer to governor adjustments in section 6.
White or Blue Exhaust Smoke
Cause: Lean fuel mixture due to: incorrect float level
Fix: Adjust carburetor float level.
Noisy Generator
Cause: Loose brush holder
Fix: Tighten brush holder

Compiled from service & troubleshooting documentation across every generator set that uses the Cummins/Onan EM (SN5782U1G2RA).

Maintenance schedule

Item	Spec	Capacity	Part #	Interval
Air filter			140-0495	150 hr	Amazon eBay $16.99 NAPA $29.20
Fuel filter			—	300 hr
Oil filter			122-0406	150 hr	Amazon eBay $17.00 NAPA $11.34
Battery			—	150 hr
Belt			—
Coolant			—
Oil	API classification, Class SG or SH oil (also SG/CD, SG/CE, SH/CD or SH/CE)	3.5 quarts	—	50 hr
Spark plug			167-0237	300 hr	Amazon eBay $14.00 NAPA $3.97

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
Genset	Other	2 hr	1 mo	Exercise at least 2 hours each month at approximately 1/2 rated power; a single 2-hour period is better than several shorter ones
Cylinder Cooling Fins	Clean	8 hr		Daily or every 8 hours; more often in dusty conditions
Engine	Inspect	8 hr		Daily or every 8 hours
Engine oil level	Check	8 hr		Every day or every 8 hours of operation (Table 4)
Exhaust system	Inspect	24 hr		Visually and audibly for leaks; daily (at least every eight hours of running time)
Fuel Lines	Inspect	8 hr		Daily or every 8 hours
General inspection	Inspect	8 hr		Every day or every 8 hours of operation (Table 4)
Oil Level	Check	8 hr		Daily or every 8 hours
Cylinder head	Adjust	25 hr		First service — Retorque before engine has run a total of 25 hours.
Cylinder head capscrews	Other	25 hr		First service — Retorque before engine has run a total of 25 hours
Cylinder heads	Adjust	25 hr		First service — Retorque before engine has run a total of 25 hours.
Cylinder head fasteners	Check	50 hr		First service — Recheck torque before engine has run a total of 50 hours (NHM)
Cylinder head nuts	Check	50 hr		First service — NHM: recheck torque before engine has run a total of 50 hours
Engine oil	Change	50 hr		First service — Break-in: change engine oil after the first 20-50 hours of operation (RV QG/RV QG RM); perform at least once a year
Spark arrester/muffler, screen type	Clean	50 hr		Remove and scrape clean or replace screen; may be blown clean with compressed air. Every 50 operating hours.
Spark arrester/muffler, spin-out type	Clean	50 hr		Remove pipe plug in bottom of muffler and run set for 5 minutes; replace plug. Every 50 hours of set operation.
Spark arresters	Clean	50 hr		Spark arresters should be cleaned every 50 to 100 hours; routine cleaning during servicing is good safety practice.
Spark arrester muffler	Clean	100 hr		Remove 1/8-inch pipe plug in bottom of muffler and run set for five minutes.
Carburetor and combustion chambers with Onan "4C"	Clean	150 hr		Dock boat outside where fumes can disperse
Engine oil and oil filter	Change	150 hr		First service — Footnotes 1,2,3,4: more often in dusty/hot conditions; at least once a year
Spark arrestor	Clean	150 hr		Spark arrestor muffler cleanout; Table 4 column inferred
Carburetor and combustion chambers	Clean	300 hr		Clean with Onan "4C"; Table 4 column inferred
Engine air filter	Replace	300 hr		Footnotes 2,4 — more often in dusty conditions, at least once a year
Engine cooling fins	Clean	500 hr		Footnotes 2,6
Fuel filter(s) and fuel pump screen	Replace	500 hr		Replace fuel filter(s) and clean fuel pump screen; footnotes 5,6
Choke vacuum sustain valve	Replace	500 hr		Footnotes 5,6 — sooner if performance deteriorates; qualified mechanic
Cylinder heads	Clean	500 hr		Removing and cleaning the cylinder heads every 500 hours is especially important for gasoline models; refer to Periodic Maintenance in the Operator's Manual
Cylinder heads and combustion chambers	Clean	500 hr		Remove cylinder heads and clean combustion chambers; footnote 6
Engine valve clearance	Adjust	500 hr		First service — Footnote 6 — must be performed by an authorized Onan dealer
Governor linkage	Inspect	500 hr		Inspect and clean; footnote 6
Spark plugs	Replace	500 hr		Footnote 4 — at least once a year; Table 4 column inferred
Stainless steel spark arrester screen	Replace	500 hr		For units using specially designed stainless steel screens.
Battery & connections	Clean		1 mo	Clean & check battery & connections; perform more often in hot weather
Flexible fuel lines	Replace		60 mo	Replace every five years as a precautionary measure; check at each service.
Oil/oil filter - Quiet Diesel 10000/12500	Change			First service — Break-in then repeat (footnotes 1-4, 2-4)
Oil/oil filter - Quiet Diesel 5500	Change			First service — Break-in then repeat (footnotes 1-4, 2-4)
Oil/oil filter - Quiet Diesel 7500/8000	Change			First service — Break-in then repeat (footnotes 1-4, 2-4)
Spark arrester	Clean		1 mo	Clean arrester; perform sooner if engine performance deteriorates
Starting Battery	Check		1 mo	Monthly; see battery manufacturer instructions
Starting battery	Clean		1 mo	Clean and check starting battery; footnote 3 — perform more often in hot weather

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	Camshaft Bearing Diameter	1.3757-1.3787	in. (34.94-35.02 mm)
Clearance	Camshaft End Play	0.011-0.048	in. (0.279-1.219 mm)
Clearance	Camshaft Journal Diameter	1.3740-1.3745	in. (34.90-34.91 mm)
Clearance	Camshaft bearing clearance	0.0015-0.0030	in (0.038-0.076 mm)
Clearance	Camshaft end play	0.003	in (0.08 mm)
Clearance	Carburetor float level	0.59-0.63	inch
Clearance	Carburetor float level (BGE)	1/16 +/- 1/32	in (1.6 +/- 0.8 mm)
Clearance	Choke plate opening (Begin Spec D gasoline)	0.337	inch	drill rod gauge
Clearance	Choke pull-off clearance	0.39 to 0.43	in (9.9 to 10.9 mm)	between choke plate and bottom of carburetor
Clearance	Choke pulloff clearance	0.39 to 0.43	inches (9.9 to 10.9 mm)
Clearance	Choke pulloff clearance	0.39-0.43	in
Clearance	Choke pulloff diaphragm clearance between choke plate and bottom of carburetor	0.39-0.43	inch
Clearance	Clearance In Cylinder	0.0044-0.0066	in. (0.112-0.168 mm)
Clearance	Clearance In Cylinder	0.0070-0.0090	in. (0.178-0.229 mm)
Clearance	Clearance between generator set and compartment walls/ceiling	0.6	inch (15 mm)
Clearance	Connecting Rod Bearing Clearance	0.0005-0.0028	in. (0.013-0.071 mm)
Clearance	Connecting Rod Side Clearance	0.0020-0.0160	in. (0.051-0.406 mm)
Clearance	Connecting Rod Side Clearance	0.0020-0.0320	in. (0.051-0.813 mm)
Clearance	Connecting rod bearing clearance	0.0020-0.0033	in (0.051-0.084 mm)
Clearance	Crankshaft Main Bearing Clearance	0.0024-0.0042	in. (0.061-0.107 mm)
Clearance	Crankshaft Main Bearing Diameter	2.0015-2.0040	in. (50.84-50.90 mm)
Clearance	Crankshaft Main Bearing Journal Diameter	1.9992-2.0000	in. (50.78-50.80 mm)
Clearance	Crankshaft Rod Journal Bearing Diameter	1.6252-1.6260	in. (41.28-41.30 mm)
Clearance	Crankshaft end play	0.006-0.012	in (0.154-0.30 mm)
Clearance	Crankshaft endplay	0.006-0.012	in
Clearance	Crankshaft main bearing clearance	0.0025-0.0038	in (0.064-0.097 mm)
Clearance	Cylinder Bore	3.2490-3.2500	in. (82.525-82.550 mm)	Std size honed
Clearance	Cylinder Bore	3.5625-3.5635	in. (90.488-90.513 mm)	Std size honed
Clearance	Cylinder Out Of Round (Max)	0.003	in. (0.076 mm)
Clearance	Cylinder Taper (Max)	0.005	in. (0.13 mm)
Clearance	Cylinder bore (std size honed)	3.2490-3.2500	in (82.525-82.550 mm)
Clearance	Exhaust system distance from combustible material	3	inches (76 mm)
Clearance	Exhaust tailpipe extension beyond vehicle perimeter	1	inch (25 mm)
Clearance	Float level	0.59-0.63	in. (15-16 mm)
Clearance	Free air inlet area	85	in2 (548 cm2)
Clearance	Front gear cover oil seal installation depth	1-1/32	in	rear spring side of casing from gear cover mounting face
Clearance	Front oil seal depth	0.97 +/- 0.02	in (24.6 +/- 0.5 mm)	from mounting face of gear cover
Clearance	Fuel injection pump installation dimension	3.260	in	new camshaft; instead of 3.254
Clearance	Governor cup travel	7/32	in (5.6 mm)	camshaft center pin extends 3/4 in (19 mm)
Clearance	LPG choke pull-off clearance (choke plate to carburetor)	0.39-0.43	in (9.9-10.9 mm)	with 4 to 18 in Hg vacuum applied
Clearance	Minimum clearance between tray and RV skirt	2	inches (51 mm)
Clearance	Minimum compartment height	14.60	inches (371 mm)
Clearance	Nikki carburetor float setting	0.59 to 0.63	in (15 to 16 mm)	measured from carburetor housing to far (bottom) side of float
Clearance	Piston Pin Clearance In Rod	0.00005-0.00055	in. (0.001-0.014 mm)
Clearance	Piston Pin Clearance In Rod	0.0002-0.0007	in. (0.005-0.018 mm)
Clearance	Piston Pin Diameter	0.6875-0.6877	in. (17.46-17.47 mm)
Clearance	Piston Pin Diameter	0.7500-0.7502	in. (19.05-19.06 mm)
Clearance	Ring Gap (top and second rings)	0.008-0.018	in. (0.20-0.46 mm)
Clearance	Ring Gap (top and second rings)	0.009-0.019	in. (0.23-0.48 mm)
Clearance	Starter brush wear limit	0.425	in (11 mm)	replace brush if worn shorter
Clearance	Starter gear lash	.020 - .010	in	pinion/ring gear engagement
Clearance	Tailpipe extension beyond perimeter of vehicle	at least 1 inch (25.4 mm)
Clearance	Valve margin (minimum)	1/16	in (1.6 mm)
Clearance	Valve seat width	0.031-0.047	in (0.79-1.19 mm)
Clearance	Valve stem clearance (exhaust)	0.0025-0.0040	in (0.064-0.102 mm)
Clearance	Valve stem clearance (intake)	0.0010-0.0025	in (0.025-0.064 mm)
Gap	Breaker point gap	0.016	in (0.41 mm)	engine static and cold
Gap	Choke breaker drill rod	8.6	mm
Gap	Piston ring gap clearance in cylinder	0.0100-0.0200	in (0.254-0.508 mm)
Gap	Point Gap	0.016	in. (0.41 mm)	Prior to Spec G

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 ethylene glycol based antifreeze and water				Mix thoroughly before adding; use clean soft tap water, distilled water or pure rain; select high quality antifreeze with corrosion inhibitors
Coolant	Ethylene glycol base anti-freeze mixed with water				Do NOT use straight 100% ethylene glycol. Normal mixture approximately 50% anti-freeze and 50% water; ratio varies with ambient temperature.
Engine oil	SAE 10W-30 / 10W-40 / 0W-30 / 5W-30				Use viscosity chart to select grade for expected ambient temperature range; avoid mixing grades or brands
Engine oil	SAE 15W-40	API CF, CF-4, CG-4, CH-4, CI-4 or CJ-4 (diesel)			OnaMax 15W-40 #326-5336; multi-grade recommended year-round in liquid-cooled engines; synthetic oil not recommended
Engine oil	SAE-30	API SJ, SL or SM (gasoline)			OnaMax SAE-30 #326-5339; preferred summer grade for optimum oil consumption control in air-cooled engines
Engine oil	5W-30	API Class SG or SH (also SG/CD, SG/CE, SH/CD or SH/CE)	-28°C to 10°C	3.5 quarts (3.3 l)	Expected ambient -20° F to 50° F (-28° C to 10° C)
Engine oil	10W-30	API Class SG or SH (also SG/CD, SG/CE, SH/CD or SH/CE)	-18°C to 27°C	3.5	0° F to 80° F
Engine oil	10W-30 / 10W-40	API Class SG or SH (also SG/CD, SG/CE, SH/CD or SH/CE)	-18°C to 27°C	3.5 quarts (3.3 l)	Expected ambient 0° F to 80° F (-18° C to 27° C)
Engine oil	10W-40	API Class SG or SH (also SG/CD, SG/CE, SH/CD or SH/CE)	-18°C to 27°C	3.5	0° F to 80° F
Engine oil	15W-40 (OnaMax)	API Class SG or SH (also SG/CD, SG/CE, SH/CD or SH/CE)	-12°C to 38°C	3.5 quarts (3.3 l)	Expected ambient 10° F to 100° F (-12° C to 38° C)
Engine oil	SAE 30	API Class SG or SH (also SG/CD, SG/CE, SH/CD or SH/CE)	above 0°C	3.5 quarts (3.3 l)	Expected ambient 32° F (0° C) and higher; single-grade SAE 30 preferable when consistently above freezing
Fuel	ASTM 2-D or 1-D diesel fuel	Cetane number 45			Use Number 1-D diesel fuel when ambient temperatures are below 32 F (0 C) or during long periods of light load/cyclic operation.
Fuel	ASTM No.2-D / No.1-D / No.2-DLS / No.1-DLS / B5 Biodiesel	minimum Cetane number 45			No.2-D or No.2-DLS above 23 degF; No.1-D or No.1-DLS below 23 degF; B5 Biodiesel above 50 degF; use No.1 diesel below 32 degF and during long light-load periods; cloud point at least 10 degF below lowest expected fuel temperature
Fuel	Gasoline				Maximum gasoline supply pressure 6 psi (41 kPa) at carburetor; maximum fuel pump lift 3 ft (0.9 m)
Fuel	Gasoline lead-free				Gasoline fueled models.
Fuel	HD-5 grade liquid propane	at least 90% propane			Fuels other than HD-5 can contain more than 2.5% butane causing poor vaporization/starting below 32 degF
Fuel	HD-5 grade liquified petroleum gas or equivalent, at least 90 percent propane				Commercial LPG may contain more than 2.5 percent butane, causing poor vaporization below 32° F (0° C)
Fuel	LPG (Liquid or Vapor Withdrawal)				Propane fueled models.
Fuel	LPG (propane)				Vapor withdrawal supply pressure 7-14 in (178-356 mm) WC; liquid withdrawal operates up to 200 psi (1379 kPa) at 110 F (43.3 C)
Fuel	Lead-Free gasoline				Propane LPG liquid or vapor withdrawal.
Fuel	Regular unleaded gasoline	Ethanol blend not more than 10% ethanol; methanol blend not more than 5% methanol			Use fresh gas, not more than 30 days old; fuel stabilizer extends fuel life
Fuel	Unleaded gasoline	minimum octane rating (Anti-Knock Index) of 87			Do not use gasoline or gasoline additives containing methanol.
Fuel	Unleaded gasoline, minimum octane rating (Anti-Knock Index) 87				Do not use gasoline or additives containing methanol; avoid highly leaded gasolines; engine certified to operate on unleaded gasoline; oxygenated gasoline acceptable but not preferable
Fuel	clean, fresh commercial propane or HD-5 grade liquid propane gas	mixture of at least 90 percent propane			For BGEL model. Propane other than HD-5 grade can contain more than 2.5 percent butane.
Fuel	clean, fresh, unleaded or regular grade gasoline				For BGE model. Do not alternate between leaded (regular) and unleaded gasoline.
Grease	GE Versilube 322-L				Apply a light coat to the starter helix outside diameter, gear inside diameter and unchamfered end of the gear
Grease	GE Versilube 322-L or equivalent				Thin film on armature shaft bearing areas; heavy coat on starter drive section of shaft
Other	Cummins Onan Premium Fuel System Cleaner			12.0 oz	Treats up to 24 gallons of gasoline; #326-5342
Other	Engine oil as lubricant for all threads EXCEPT spark plug and rotor through-bolt threads				Torque Specifications section.
Other	Locktite Bearing Mount				Front crankshaft bearing installation; allow one hour hardening.

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 anti-dieseling solenoid adjustment

With set stopped, turn lever counterclockwise; set screw so plates are closed but not binding.
Check lever has approximately 30 degrees travel counterclockwise from vertical.
Start set; lever should rotate approximately 60 degrees clockwise from stopped position.
Check solenoid plunger is fully seated.
If not, adjust distance between plunger and lever arm; repeat steps.

Automatic Choke Adjustment adjustment

Tools: vacuum source, drill rod, pliers

Apply at least 100 mm mercury vacuum to choke breaker.
Insert 8.6 mm drill rod between choke plate and throat.
Bend link until choke plate lip touches drill rod.
Use two pliers to bend link.

Breaker Point Replacement and Adjustment adjustment

⚠ Ignition adjustments must be made with engine static and cold

Tools: Hex head socket, Socket wrench, Allen head wrench, Flat thickness gauge

Disconnect negative battery cable at battery terminal.
Remove breaker box cover clip and lift off cover.
Remove spark plugs; rotate rotor through-bolt clockwise until points open maximum.
Remove condenser mounting screw and disconnect condenser and ignition leads.
Remove breaker point mounting screws and lift out point assembly.
Install new condenser and points in reverse order of removal.
Adjust setscrew to specified point gap (0.016 in / 0.41 mm).
Replace cover and spark plugs; reconnect negative battery cable.

Breaker Point Replacement/Adjustment adjustment

⚠ Make ignition adjustments with the engine cold and at rest; do not file the points

Tools: Socket wrench, Allen wrench, Flat thickness gauge

Disconnect the negative (-) battery cable at the battery terminal.
Remove the breaker box cover clip and lift off the cover.
Remove spark plugs; turn the rotor through-bolt clockwise until the point gap is fully open.
Disconnect the ignition lead wire at screw A.
Remove the breaker point mounting screws (B) and lift out the point assembly.
Replace the breaker point assembly.
Adjust setscrew C to the specified gap (0.016 in / 0.41 mm) using a flat thickness gauge.
Replace the cover, spark plugs, leads, and reconnect the negative battery cable.

Carburetor Fuel Mixture Adjustment adjustment

⚠ Forcing mixture screws tight damages needle and seat.

Tools: voltmeter, frequency meter, load bank

Stop set and connect voltmeter, frequency meter, and load bank.
Start set and apply full load; adjust governor speed nut to 59 (49) ±2 Hz.
Remove main adjustment limiter cap; turn main screw inward until voltage or frequency drops.
Turn outward until voltage or frequency drops again; locate highest point.
Turn main adjustment screw out another 1/4 turn.
Remove load and verify frequency within 62-63 Hz (51.5-52.5 Hz).
Adjust idle screw for smoothest operation without hunting.
Replace limiter caps with lever at mid position.

Carburetor Mixture Screw Adjustment (Gasoline) adjustment

⚠ Forcing mixture adjustment screws tight will damage needle and seat

Tools: Voltmeter, Frequency meter, Load bank, Screwdriver

Stop set; connect voltmeter, frequency meter, and load bank.
Start set and apply load; verify frequency within 59 (49) +/- 2 hertz.
Turn main adjustment screw in, then out, to point of highest voltage and frequency.
Turn main adjustment screw out an additional 1/4 turn.
Remove load; verify frequency within 62 (51.5) +/- 1 hertz.
Adjust idle adjustment screw for smoothest operation without hunting.
Adjust throttle stop screw to obtain 55 (45) +/- 1 hertz.

Carburetor adjustment for 6.5 NH RV adjustment

Turn idle mixture screw out 3/4 to 1 turn from seated.
Turn main mixture screw 1-1/2 to 1-3/4 turns out from seated.
Start set; adjust governor spring for 1860 RPM no load (62 Hz or 130 volts).
Hold governor arm so throttle lever rests on stop; adjust idle stop screw to 1500 RPM (50 Hz or 100 volts); release.
Adjust idle mixture screw to highest RPM or voltage; readjust governor spring to 1860 RPM no load.
Apply full load; adjust main mixture screw to highest RPM or voltage; readjust governor spring to 1770 RPM full load.
Remove and add load several times to check hunting; readjust governor spring if required.

Choke Adjustment adjustment

Stop set and allow to cool.
Remove plastic choke cover and loosen heating element cover screws.
Rotate heating element until choke plate is halfway open.
Rotate cover counterclockwise while tapping choke lever until it no longer bounces.
Refer to Table 6-2 to determine degrees clockwise from reference.
Rotate element cover as specified and tighten screws.
Move choke lever to test free operation; install plastic cover.

Droop Adjustment adjustment

Connect rated load; load watts = volts x amps (1.0 power factor).
Check droop from no-load frequency.
If droop more than 3 Hz (BGE) or 4 Hz (NHE), turn governor sensitivity screw one turn counterclockwise.
Disconnect load and readjust governor speed screw to 62-63 Hz no-load if necessary.
If droop less than 2 Hz (BGE) or 3 Hz (NHE), turn sensitivity screw one turn clockwise.
Check governor response under 1/4, 1/2 and 3/4 rated loads.

Engine Speed Adjustments adjustment

⚠ Adjusting engine speed above equipment manufacturer's specification could cause equipment to operate at speeds in violation of Federal and State Standards for Safety.

⚠ Moving parts can cause severe personal injury or death. Take care when measuring engine speed with tachometer. Must be qualified mechanic.

Tools: Accurate tachometer

Adjust only by qualified mechanic using accurate tachometer.
Set low-idle and high-idle speeds to values in equipment Operator's Manual. If absent, adjust low-idle to 1400 RPM and high-idle to 3400 RPM.
Start engine and move throttle lever to lowest speed position.
Adjust low-idle speed stop screw on carburetor to obtain specified low-idle speed.
For cable controlled engines: move throttle lever to highest speed position. Loosen high-idle speed stop plate clamping screw and rotate stop plate while holding throttle control arm against it until
For lever controlled engines: adjust lever stop screw while holding throttle lever against it until specified high-idle speed is obtained.
Check for full, smooth movement of throttle control arm between stop positions.

Frequency Adjustment adjustment

⚠ Disconnect voltage/frequency sensitive devices before adjustments.

Set altitude adjust knob (gasoline only) to your altitude.
Disconnect all loads and check no-load frequency.
Turn governor speed adjusting screw to obtain 62-63 Hz (51.5-52.5 Hz for 50 Hz).
Check output voltage; see Generator if not within 10 percent of rated.
See Troubleshooting if engine runs roughly.

Frequency Adjustments adjustment

Tools: frequency meter, voltmeter

Set altitude adjust knob to altitude (gasoline only).
Disconnect all loads and check zero amps.
Adjust governor speed screw for 62-63 Hz no-load (51.5-52.5 Hz).
Check output voltage within 10 percent of rated voltage.

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
		Battery charging / choke heater	B1 and B2 to control printed circuit board harness J1 and to rectifier CR10
		Brush block	F1 (+) outboard brush terminal and F2 (-) inboard brush terminal; VR1 leads J4-9/F1 and J4-10/F2
		Field excitation	Q1 and Q2 to voltage regulator VR1 harness J4 (J4-11/Q1 and J4-12/Q2)	Reference voltage is J4-2/L1 to J4-3/L0
		Stator leads B1 and B2 to Control Board A1 wiring harness J1	B1,B2	Supplying power to generator relay K2
		Stator leads Q1 and Q2 to Voltage Regulator VR1 wiring harness J4	Q1,Q2	Excitation voltage of rotor
		Stator leads T1, T2, T3, T4 to Terminal Board TB1	T1,T2,T3,T4	Supplying power to load
		Terminal 1 - Ground	Black	Remote switch wire color code
		Terminal 2 - Stop	Brown	Remote switch wire color code
		Terminal 3 - Start	Yellow	Remote switch wire color code
		Terminal 6 - Lamp and running time meter	Red	Remote switch wire color code
110-120 V	1	2 wire	T3 to TB1-L1; T4 to TB1-L0; move TB1-L2 to CB2 and TB1-L1 to CB2	Connect output leads (CB1 to load and CB2 to load) together to load
110/120V	1	T2 L3, T4 L3	T1, T2, T3, T4	1 PH 4 wire reconnection chart.
110/220	1	S1 lead wire to transformer X3 tap; CR4-AC lead wire to transformer X5 tap	S1, CR4-AC	50 Hz standard setting; increase/decrease voltage by changing transformer secondary tap connections
120	1	S1 lead wire to transformer X2 tap; CR4-AC lead wire to transformer X5 tap	S1, CR4-AC	60 Hz standard setting; preliminary connection may require adjustment for correct output voltage
120/240	1	Standard setting taps X1, X3; adjust secondary taps to increase or decrease voltage	S1, CR4-AC	50 Hz; refer to Table 8-1 Transformer Tap Connections
120/240 V	1	Standard connection, 3 wire	T1 to L1 (CB1); T2 to LO; T3 to L2; T4	*T2 is the grounded AC lead; refer to drawings 611-1215, 611-1216, 611-1210, 611-1182
120/240V	1	120/240V	T1 L1, T2 L3, T3 L2, T4 L3	See applicable wiring diagram/schematic for specific connections.
120/240V	1	T1 L1, T3 L2, T2 L3	T1, T2, T3, T4	120V max across VR1 connections 2,3. For isolated neutral remove jumper W2 TB1-L3-LO and connect jumper TB1-LO.
120V	1	120V max across VR1 connections 2,3		Grounded AC lead—for isolated neutral, remove jumper (W2) TB1-L3, LO and connect jumper TB1-LO. VR1-C5 negative.
120V	1	4.0 KW genset, 30 amp shore power	L1, L0, GND	Double-pole double-throw switch used for switching
120V, 1PH	1	Stator output leads to terminal board	T1, T2, T3 and T4 to terminal board TB1 at terminals L1 - L0
120V/240V	1	5.0-6.5 KW genset and 50-amp shore power	L1, L2, N, GND	50 amp 3-pole transfer switch with neutral rated at least 60 amp; neutral conductor must have ampacity of at least 60 amps
220-240 V	1	2 wire	T4 to TB1-L1; remove TB1-L1 to CB1	Connect to output load lead (black)
220/240V	1	T1 L1, T3 L2	T1, T2, T3, T4	1 PH 4 wire reconnection chart.

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 EM (SN5782U1G2RA)?

The Cummins/Onan EM (SN5782U1G2RA) engine has an oil capacity of 3.3 liters.

What is the displacement of the Cummins/Onan EM (SN5782U1G2RA)?

The Cummins/Onan EM (SN5782U1G2RA) has a displacement of 0.782 liters with 2 cylinders.

Which generators use the Cummins/Onan EM (SN5782U1G2RA) engine?

The Cummins/Onan EM (SN5782U1G2RA) powers 1 generator set(s), including Cummins/Onan 4000.

How often should you change the oil in the Cummins/Onan EM (SN5782U1G2RA)?

The Cummins/Onan EM (SN5782U1G2RA) oil change interval is every 50 hours.

What is a common problem with the Cummins/Onan EM (SN5782U1G2RA) engine?

A commonly reported issue on generators using the Cummins/Onan EM (SN5782U1G2RA) is: Engine Does Not Crank. Cause: If engine cranks at set but not at remote control panel, fault is due to PC board P2/J2 connection not secure. Fix: Ensure that wiring harness jack connections are fully seated to PC board.