The Cummins/Onan EM (SN5782U1G2RA) is a 782 L 2-cylinder engine rated at 1800 rpm. It powers generator sets from Cummins/Onan, including the 4000 and BGE. It holds 3.3 L (0.9 gal) of oil.
Also known as: Onan EM (SN5782U1G2RA)
| Oil capacity | 3.3 L |
|---|---|
| Displacement | 782.0 L |
| Cylinders | 2 |
| Rated speed | 1800 rpm |
How to read your Cummins/Onan engine serial & model number →
Compiled from service & troubleshooting documentation across every generator set that uses the Cummins/Onan EM (SN5782U1G2RA).
| Item | Spec | Capacity | Part # | Interval | |
|---|---|---|---|---|---|
| Air filter | — | 150 hr | |||
| Fuel filter | — | 300 hr | |||
| Oil filter | — | 150 hr | |||
| 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 | — | 300 hr |
Pooled from every document that names this exact engine — confirm the interval and part number against your unit's serial number.
| Item | Action | Hours | Months | Notes |
|---|---|---|---|---|
| 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 | 8 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) | |
| Generator set | Inspect | 8 hr | Perform general inspection every eight operating hours; with set running visually and audibly check exhaust system for leaks | |
| Oil Level | Check | 8 hr | Daily or every 8 hours | |
| Oil and fuel leaks | Check | 8 hr | Before operating the set each day, or at least every 8 hours; check exhaust system audibly and visually with generator set running. | |
| 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. | |
| Battery electrolyte level | Check | 50 hr | ||
| Engine oil and oil filter | Change | 50 hr | First service — Footnotes 1,2,3,4 - part of engine break-in change oil after first 50 hours; more often in dusty (every 50 hours) and hot weather; perform at least once a year | |
| Spark arrester | Clean | 50 hr | ||
| Spark arrestor | Clean | 50 hr | Spark arrestor muffler | |
| Spark arrester muffler | Clean | 100 hr | Remove 1/8-inch pipe plug in bottom of muffler and run set for five minutes. | |
| Air filter | Change | 150 hr | 12 mo | Perform more often in extremely dusty conditions |
| Carburetor and combustion chambers with Onan "4C" | Clean | 150 hr | Dock boat outside where fumes can disperse | |
| Crankcase oil and oil filter | Change | 150 hr | First service — Every 150 operating hours or once a year, whichever is first; first oil change during first year or 50 hours of operation | |
| Engine air filter | Replace | 150 hr | Footnotes 2,4 - more often in dusty conditions; perform at least once a year | |
| Engine oil | Change | 150 hr | 12 mo | First service — First oil change during first year or 50 hours of operation, whichever is first; then every 150 hours |
| Choke vacuum sustain valve | Replace | 300 hr | Footnotes 5,6 - sooner if engine performance deteriorates; must be performed by a qualified mechanic | |
| Engine cooling fins | Clean | 300 hr | Footnotes 2,6 | |
| Fuel filter(s) and fuel pump screen | Replace | 300 hr | Replace fuel filter(s) and clean fuel pump screen; footnotes 5,6 | |
| Spark plugs | Replace | 500 hr | Footnote 4 - perform at least once a year | |
| Carburetor and combustion chamber | Clean | 500 hr | With Onan "4C" Cleaner | |
| Combustion chamber | Inspect | 500 hr | Internal inspection by an Onan service representative after approximately 500 hours. | |
| 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 a qualified mechanic (authorized Onan dealer) | |
| Fuel filter | Replace | 500 hr | Replace fuel filter at carburetor, clean screen at fuel pump | |
| Governor linkage | Inspect | 500 hr | Inspect and clean; footnote 6 | |
| Air filter | Check | 1 mo | Check monthly in extremely dusty conditions; change if dirty. | |
| Air filter | Replace | 12 mo | Or once a year, whichever is first. | |
| Fuel filter (BGEL-LPG fuel) | Replace | 12 mo | Equipped on BGEL; customer option for BGE models. Replace annually or prior to storage, whichever is first | |
| Generator set | Clean | 6 mo | Every six months or more often if severe contamination; also as required | |
| Generator set | Test | 1 mo | Exercise for 2 hours at 50 percent capacity every 4 weeks during periods of nonuse | |
| 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.
| 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 (BGE) | 1/16 +/- 1/32 | in (1.6 +/- 0.8 mm) | |
| 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 | 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 oil seal depth | 0.97 +/- 0.02 | in (24.6 +/- 0.5 mm) | from mounting face of gear cover |
| Clearance | Governor cup travel | 7/32 | in (5.6 mm) | camshaft center pin extends 3/4 in (19 mm) |
| 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 | 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 | Breaker point gap | see SPECIFICATIONS section | measured with flat thickness gauge, engine static and cold; value not legible in source | |
| 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 |
| Gap | Spark Plug Gap | 0.035 inches (0.89 mm) | inches (mm) | |
| Gap | Spark plug gap | 0.025 | inches (0.64 mm) | |
| Gap | Spark plug gap | 0.64 | mm | |
| Gap | Spark plug gap | see SPECIFICATIONS section | value not legible in source | |
| Injection timing | Ignition timing | 12 | degrees BTDC | electronic ignition, non-adjustable |
| Other | Battery capacity | 60 | Amperes | |
| Other | Battery cranking current | 360 | Cold Cranking Amperes | |
| Other | Battery electrolyte specific gravity | 1.215 | charge if specific gravity measures less than this |
Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.
| Fluid | Grade | Standard | Ambient | Capacity | Notes |
|---|---|---|---|---|---|
| Engine oil | API SG | MS Sequence Tests (ASTM G-1V Sequence Tests) | 3.8 L | SAE viscosity grades per chart: 20W-40, 20W-50, 10W-30, 10W-46; single-grade oils preferable unless wide temperature variations anticipated | |
| Engine oil | SAE 10W-30, 10W-40 | API SF, SF/CC, or SF/CD | 3.3 L | See SAE Viscosity Grades chart (Figure 4-2). | |
| Engine oil | SAE 15W-40 | API SF, SF/CC, or SF/CD | 3.3 L | See SAE Viscosity Grades chart (Figure 4-2). | |
| Engine oil | SAE 5W-30 | API SF, SF/CC, or SF/CD | 3.3 L | See SAE Viscosity Grades chart (Figure 4-2). | |
| Engine oil | SAE viscosity per oil chart (Figure 6) | API designation SF; passed MS Sequence Tests (ASTM G-IV) | 4.0 U.S. quarts (3.8 l) | Includes filter. Single grade oils generally desirable unless wide temperature range; oil consumption can be higher with multigrade oil | |
| 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 | 1.0 quart | |
| 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 | 1.0 quart | |
| 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 |
| Engine oil | SAE 30W | API SF, SF/CC, or SF/CD | above 0°C | 3.3 L | Straight weight oils recommended for severe duty use and at temperatures above 32 F (0 C) for minimum oil consumption. See SAE Viscosity Grades chart (Figure 4-2). |
| Fuel | Clean, fresh unleaded or regular grade gasoline | Gasoline models. Lead deposits from regular gasoline must be removed from cylinder head areas. | |||
| Fuel | Commercial propane or HD-5 grade liquid propane gas, mixture of at least 90 percent propane | HD-5 | LPG models. Fuels other than HD-5 can contain more than 2.5 percent butane. | ||
| Fuel | Gasoline lead-free | Gasoline fueled models. | |||
| Fuel | LPG (Liquid or Vapor Withdrawal) | Propane fueled models. | |||
| Fuel | Lead-Free gasoline | Propane LPG liquid or vapor withdrawal. | |||
| 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 | Unleaded gasoline; regular leaded may be used if necessary | Use fuel preservative/stabilizer such as OnaFresh if set will not be operated for more than 120 days | |||
| 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 commercial propane or HD-5 grade liquid propane gas, mixture of at least 90 percent propane | NFPA 501C Section 3-5 paragraphs 1.1 and 1.2; Canadian Gas Association Bulletin 6149.2-78 | BGEL model. Propane other than HD-5 can contain more than 2.5 percent butane causing poor starting below 32 F (0 C) | ||
| Fuel | clean, fresh unleaded or regular grade gasoline | BGE model. If regular gasoline used, lead deposits must be removed from cylinder heads as required | |||
| 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 light coat to starter helix and gear. | |||
| Grease | GE Versilube 322-L or equivalent | Thin film on armature shaft bearing areas; heavy coat on starter drive section of shaft | |||
| 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. | |||
| Other | Loctite #680 adhesive / Loctite #747 activator | Rotor bearing installation; allow ten minutes curing. | |||
| Other | OnaFresh fuel preservative (stabilizer) | Add to fresh fuel before storage per container label; toxic |
Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.
Tools: vacuum source, drill rod, pliers
⚠ Ignition adjustments must be made with engine static and cold
Tools: Hex head socket, Socket wrench, Allen head wrench, Flat thickness gauge
⚠ Forcing mixture screws tight damages needle and seat.
Tools: voltmeter, frequency meter, load bank
⚠ Forcing mixture adjustment screws tight will damage needle and seat
Tools: Voltmeter, Frequency meter, Load bank, Screwdriver
⚠ 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
⚠ Disconnect voltage/frequency sensitive devices before adjustments.
Tools: frequency meter, voltmeter
⚠ Use extreme caution when making adjustments while engine is running
Tools: Voltmeter, Frequency meter
⚠ Too much pressure on rod can result in faulty adjustment.
Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.
| Voltage | Phase | Connection | Leads | Notes |
|---|---|---|---|---|
| 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 | ||
| 110/120V | 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 |
| 120/240V | 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/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 |
| 220/240V | 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.
The Cummins/Onan EM (SN5782U1G2RA) engine has an oil capacity of 3.3 liters.
The Cummins/Onan EM (SN5782U1G2RA) has a displacement of 782.0 liters with 2 cylinders.
The Cummins/Onan EM (SN5782U1G2RA) powers 2 generator set(s), including Cummins/Onan 4000, Cummins/Onan BGE.
The Cummins/Onan EM (SN5782U1G2RA) oil change interval is every 50 hours.
A commonly reported issue on generators using the Cummins/Onan EM (SN5782U1G2RA) is: There is no electrical power even though the genset runs.. Fix: A. Reset tripped circuit breakers. See Powering Equipment. b. Unless there is an automatic power transfer switch, plug the boat power cord into the genset power output receptacle (if so equipped) or turn the pontoon boat power selector switch to its genset position (if so equipped)..