The Cummins/Onan EGMBU (P5000e) is a 0.39 L engine rated at 3000 rpm. It powers generator sets from Cummins/Onan, including the EGMBU. It holds 1.16 L (0.3 gal) of oil.
Also known as: Cummins Onan EGMBU (P5000e)
| Oil capacity | 1.16 L |
|---|---|
| Displacement | 0.389 L |
| Rated speed | 3000 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 EGMBU (P5000e).
Step-by-step procedures compiled from the Cummins/Onan service manual for this engine.
| Item | Action | Hours | Months | Notes |
|---|---|---|---|---|
| Engine Oil | Change | 100 hr | 6 mo | First service — First month or 20 hours (also change after first 20 hours of engine break-in) |
| Air Cleaner | Clean | 50 hr | 3 mo | Every 3 months or 50 hours; service more frequently in dusty environments (footnote 2) |
| Cylinder Cooling Fins | Clean | 50 hr | 3 mo | Every 3 months or 50 hours; service more frequently in dusty environments (footnote 2) |
| Spark Plug | Clean | 100 hr | 6 mo | Every 6 months or 100 hours |
| Starting Battery | Check | 100 hr | 6 mo | If equipped |
| Fuel Sediment Cup | Clean | 300 hr | 12 mo | Must be performed by a trained and experienced mechanic |
| Fuel Tank | Clean | 300 hr | 12 mo | Must be performed by a trained and experienced mechanic |
| Spark Arrestor | Clean | 300 hr | 12 mo | Every year or 300 hours |
| Valve Clearance | Adjust | 300 hr | 12 mo | Must be performed by a trained and experienced mechanic |
| Valve Lash | Adjust | 300 hr | 12 mo | Every year or 300 hours; must be performed by a trained and experienced mechanic (authorized Onan/Cummins Onan dealer) |
| Fuel Line | Check | 24 mo | Every 2 years (replace if necessary); footnote 3 — authorized Onan/Cummins Onan dealer | |
| General Inspection | Inspect | First service — See General Inspections; check before first start of the day and after every 8 hours of operation |
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 | Big End Oil Clearance | 0.024 - 0.059 | mm (0.0009 - 0.0023 in) | allowable limit 0.12 mm (0.0048 in) |
| Clearance | Big End Side Clearance | 0.25 - 0.65 | mm (0.0098-0.0256 in) | allowable limit 1.0 mm (0.04 in) |
| Clearance | Cam Height Exhaust | 31.57 - 31.97 | mm (1.243 - 1.259 in) | allowable limit 31.80 mm (1.252 in) |
| Clearance | Cam Height Intake | 31.85 - 32.25 | mm (1.254 - 1.270 in) | allowable limit 31.10 mm (1.224 in) |
| Clearance | Camshaft O.D. | 15.984 | mm (0.6293 in) | allowable limit 15.92 mm (0.627 in) |
| Clearance | Connecting Rod Big/Large End I.D. (Crankshaft) | 36.015 | mm (1.4179 in) | allowable limit 36.07 mm (1.420 in) |
| Clearance | Connecting Rod Small End I.D. (Pin End) | 20.007 | mm (0.7877 in) | allowable limit 20.07 mm (0.790 in) |
| Clearance | Crankcase Cover Camshaft Holder I.D. | 16.00 | mm (0.63 in) | allowable limit 16.05 mm (0.632 in) |
| Clearance | Crankshaft O.D. (Connecting Rod Large End) | 35.991 | mm (1.417 in) | allowable limit 35.93 mm (1.4145 in) |
| Clearance | Cylinder Head Warpage (allowable limit) | 0.10 | mm (0.004 in) | |
| Clearance | Cylinder Sleeve I.D. (factory / allowable) | 82.015 mm (3.229 in) / 82.17 mm (3.235 in) | mm | |
| Clearance | Cylinder Sleeve I.D. (factory / allowable) | 88.015 mm (3.465 in) / 88.17 mm (3.4713 in) | mm | |
| Clearance | Guide-to-Stem Clearance Exhaust | 0.04 - 0.067 | mm (0.0016 - 0.0026 in) | allowable limit 0.13 mm (0.005 in) |
| Clearance | Guide-to-Stem Clearance Intake | 0.02 - 0.047 | mm (0.00078 - 0.0019 in) | allowable limit 0.11 mm (0.004 in) |
| Clearance | Piston Pin Bore I.D. | 20.002 | mm (0.7875 in) | allowable limit 20.042 mm (0.7891 in) |
| Clearance | Piston Pin O.D. | 20.007 | mm (0.7877 in) | allowable limit 19.95 mm (0.785 in) |
| Clearance | Piston Ring End Gap (Top/Second/Oil) | 0.2 - 0.4 | mm (0.008-0.016 in) | allowable limit 1.0 mm (0.04 in) |
| Clearance | Piston Ring Side Clearance (Top/Second/Oil) | 0.015 - 0.045 | mm (0.0006 - 0.0018 in) | allowable limit 0.15 mm |
| Clearance | Piston Skirt O.D. (factory / allowable) | 81.97 mm (3.227 in) / 81.85 mm (3.222 in) | mm | |
| Clearance | Piston Skirt O.D. (factory / allowable) | 87.97 mm (3.463 in) / 87.85 mm (3.459 in) | mm | |
| Clearance | Piston-to-Cylinder Clearance | 0.045-0.075 | mm (0.0018-0.0295 in) | allowable limit 0.12 mm (0.005 in) |
| Clearance | Piston-to-Piston Pin Bore Clearance | 0.004 - 0.016 | mm (0.00016 - 0.0006 in) | allowable limit 0.08 mm (0.0031 in) |
| Clearance | Starter Motor Brush Length | 7.0 | mm (0.28 in) | allowable limit 3.5 mm (0.14 in) |
| Clearance | Starter Motor Mica Depth | 1.0 | mm (0.04 in) | allowable limit 0.2 mm (0.008 in) |
| Clearance | Valve Guide I.D. IN/EX | 6.60 | mm (0.260 in) | allowable limit 6.66 mm (0.262 in) |
| Clearance | Valve Seat Width | 1.1 | mm (0.04 in) | allowable limit 2.0 mm (0.08 in) |
| Clearance | Valve Spring Free Length | 39.0 | mm (1.54 in) | allowable limit 37.5 mm (1.48 in) |
| Clearance | Valve Stem O.D. Exhaust | 6.56 | mm (0.258 in) | allowable limit 6.40 mm (0.252 in) |
| Clearance | Valve Stem O.D. Intake | 6.58 | mm (0.259 in) | allowable limit 6.44 mm (0.254 in) |
| Gap | Ignition Coil Air Gap (at flywheel) | 0.4 ±0.2 | mm (0.016 ±0.008 in) | |
| Gap | Spark Plug Gap | 0.028 | in. (0.7 mm) | |
| Gap | Spark Plug Gap | 0.7 - 0.8 | mm (0.028 - 0.031 in) | |
| Injection timing | Ignition Timing (Fixed) | 25 | o BTDC | |
| Other | Battery electrolyte specific gravity | 1.270 - 1.290 | ||
| Other | Carbon Brush Length | 5 - 9 | mm | replace if less than 5 mm (0.20 in) |
| Other | Carburetor pilot screw initial opening | 1-5/8 | turns out | |
| Other | Valve Head Diameter | In = 24 mm (0.94 in), Ex = 22 mm (0.87 in) | mm | |
| Pressure | Cylinder Compression | 5.0-8.5 | kg/cm (79 - 121 lbs/in) | at 600 rpm |
| Resistance | Charging Coil Resistance (wire terminal to ground) | 7.5 - 12.5 | KΩ | electric start models |
| Resistance | Exciter Winding (Bu / Bu) Resistance | 2.452 - 3.052 | Ω | |
| Resistance | Exciter Winding (Bu / Bu) Resistance | 2.635 - 3.035 | Ω | |
| Resistance | Field Winding Resistance (slip rings) | 41 - 51 | Ω | |
| Resistance | Field Winding Resistance (slip rings) | 44 - 54 | Ω | |
| Resistance | Ignition Coil Primary Coil Resistance | 0.8 - 1.0 | Ω | |
| Resistance | Ignition Coil Secondary Coil Resistance | 5.9 - 7.1 | KΩ | spark plug cap removed |
| Resistance | Main Winding (DC) (G / G) Resistance | 0.143 - 0.18 | Ω | |
| Resistance | Main Winding (DC) (G / G) Resistance | 0.153 - 0.193 | Ω | |
| Resistance | Main Winding I (Br / W) Resistance | 0.158 - 0.194 | Ω | |
| Resistance | Main Winding I (Br / W) Resistance | 0.213 - 0.253 | Ω | |
| Resistance | Spark Plug Cap Resistance | 5 | KΩ | |
| Resistance | Starter Motor Armature Changing Resistance (Coil) | 3.5 ±0.5 | Ω | |
| Resistance | Starter Solenoid Resistance | >1 | MΩ | 12V battery connected between starter terminal and solenoid body |
| Speed | Engine Speed | 3000 | RPM | |
| Speed | Governor idle speed (set with limiting screw) | 3600 ±150 | RPM | engine warm |
| Speed | Idle Speed | 2000 ±200 | rpm | |
| Speed | Maximum Speed | 3180 ±150 | rpm | |
| Torque | Air cleaner mounting nut | 7 - 10 | N·m (70 - 100 kg·cm, 5.1 - 7.2 ft-lb) | 6×1.0 mm |
| Torque | Air cleaner wing nut | 7 - 10 | N·m (70 - 100 kg·cm, 5.1 - 7.2 ft-lb) | 6×1.0 mm |
| Torque | Connecting rod bolt | 12 - 16 | N·m (120 - 160 kg·cm, 8.7 - 11.5 ft-lb) | 8×1.25 mm |
| Torque | Crankcase cover bolt | 22 - 26 | N·m (220 - 260 kg·cm, 15.9 - 18.8 ft-lb) | 8×1.25×35 mm |
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 | SAE 10W-30 (recommended for general, all-temperature use) | American Petroleum Institute (API) SG - SF/CC - CD; also API performance class SL or SJ or better | 1.1 L | Engine Oil Capacity = 1.16 US quart (1.1 liters) | |
| Engine oil | 5W-30 | API SL or SJ or better | -28°C to 10°C | -20o F to 50o F | |
| Engine oil | 10W-40 | API SL or SJ or better | -18°C to 27°C | 0o F to 80o F | |
| Engine oil | 10W-30 | API SL or SJ or better | -12°C to 38°C | 10o F to 100o F | |
| Engine oil | 15W-40 | API SL or SJ or better | -12°C to 38°C | 10o F to 100o F | |
| Engine oil | SAE 30 | API Class SL or SJ or better | above 0°C | 1.1 L | Best when temperatures are consistently above freezing; 32°F (0°C) and higher |
| Engine oil | SAE 30 (single-grade) | API SL or SJ or better | above 0°C | Best when temperatures are consistently above freezing; 30o F (0 C) and higher | |
| Fuel | Clean, fresh unleaded gasoline with an octane rating (anti-knock index) of 87 or higher | 24.6 L | Fuel tank capacity 6.5 US gal (24.6 L). Do not use gasoline or additives containing methanol; avoid leaded gasoline | ||
| Fuel | Unleaded gasoline, octane rating (anti-knock index) 87 or higher | 24.6 L | Fuel tank capacity 6.5 US Gal (24.6 L). Do not use starting fluids; do not use gasoline or additives containing methanol. Leaded gasoline requires extra maintenance. |
Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.
⚠ Valve clearance inspection and adjustment must be performed with the engine cold.
Tools: Feeler gauge
⚠ Only use soapy water or a nonflammable solvent for cleaning components.
⚠ Never run the engine without the air cleaner installed.
⚠ Arcing at battery terminals can ignite battery gases causing severe personal injury. Ventilate the area, wear safety glasses, do not smoke.
⚠ If used before a starting battery is installed, insulate the red battery cable terminal with electrical insulating tape to prevent short circuits.
⚠ Connect the blue wire lead to the positive (+) side of the brush holder.
⚠ Contact with used engine oil can cause cancer and reproductive toxicity. Avoid skin contact and breathing of vapors.
⚠ Wear safety glasses to protect your eyes from flying debris when cleaning with compressed air.
⚠ Cleaning with a pressure washer can cause damage by shorting the generator and other electrical components.
Tools: Damp cloth, Compressed air (optional), Safety glasses
⚠ Contact with a hot muffler can cause severe burns. Allow the generator set to cool before servicing the muffler.
Tools: Wire brush
⚠ A hot muffler can cause severe burns. Allow the generator set to cool before servicing the muffler.
Tools: Wire brush
⚠ Gasoline is highly flammable and explosive. After reassembly, check for leaks and make sure the area is dry before starting the engine.
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 |
|---|---|---|---|---|
| 120 | Voltage selector switch: 4 connects to 1, 5 connects to 2, and 6 connects to 3 | 4-1, 5-2, 6-3 | Measure continuity with switch wires unplugged | |
| 240 | Voltage selector switch: 1 connects to 7, 2 connects to 8, and 3 connects to 9 | 1-7, 2-8, 3-9 | Measure continuity with switch wires unplugged |
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 EGMBU (P5000e) engine has an oil capacity of 1.16 liters.
The Cummins/Onan EGMBU (P5000e) has a displacement of 0.389 liters.
The Cummins/Onan EGMBU (P5000e) powers 1 generator set(s), including Cummins/Onan EGMBU.
A commonly reported issue on generators using the Cummins/Onan EGMBU (P5000e) is: NO DC OUTPUT. Cause: · Tripped DC circuit breaker. Fix: 1. Disconnect the battery. 2. Reset the circuit breaker. 3. Have the battery tested for shorts and, if necessary, replace the battery..