Cummins/Onan 7.5 MDKWB Generator Set

⚠ Do not operate genset without belt guard in place.

⚠ Operation with too much tension may cause reduced belt life.

Tools: wrench

1. Disable genset by disconnecting battery cables (negative first).
2. Remove belt guard.
3. Loosen bottom pivot bolt on alternator.
4. Loosen bolt through long slot in alternator mounting bracket.
5. Slide alternator until tension is right.
6. Tighten bolts.
7. Replace belt guard.

⚠ Batteries present explosion hazard.

⚠ Battery electrolyte can cause severe eye damage and burns.

Tools: battery hydrometer, terminal puller

1. Keep battery case clean and dry.
2. Make certain battery cable connections are clean and tight. Use terminal puller to remove cables.
3. Remove corrosion from terminals; wash with ammonia solution or baking soda solution. Flush with clean water.
4. Identify positive (+) or negative (-) cable before making connections. Always connect negative (-) cable last.
5. Maintain electrolyte level by adding distilled water. Fill each cell to split-level marker.
6. Use battery hydrometer to check specific gravity. Charge if less than 1.215. Stop charging when specific gravity reaches 1.260 at approximately 80°F (27°C).

⚠ Hot crankcase oil can cause burns.

⚠ Prolonged contact with used engine oil can cause cancer or reproductive toxicity.

1. Run engine until thoroughly warm.
2. Stop engine.
3. Open oil drain valve and drain oil into container.
4. Close valve when completely drained.
5. Refill crankcase with new oil of recommended type.

⚠ Contact with hot coolant can cause serious burns.

⚠ Do not bleed hot, pressurized coolant from a closed cooling system.

1. Verify all drain cocks closed and hose clamps secure.
2. Remove cooling system pressure cap.
3. Slowly fill cooling system with coolant mixture.
4. Fill recovery tank to FULL mark.
5. Operate genset until normal operating temperature (about 15 minutes).
6. Shut down and let cool.
7. Add coolant to recovery tank until level stabilizes at Full mark; may require several cycles.

⚠ Never pour hot water into a cold engine or cold water into a hot engine.

⚠ Do not operate the unit without water.

1. Open heat exchanger drain and cylinder block drain.
2. Remove pressure cap to aid draining.
3. Drain system completely.
4. Chemical cleaning: use good cleaning compound per instructions if rust/scale.
5. Flushing: fill with clean water, run genset 10 minutes, drain completely.
6. Refill with coolant mixture.

⚠ Inhalation of exhaust gases can cause severe personal injury or death.

⚠ Fuel leakage will create a fire hazard.

⚠ Ignition of explosive battery gases can cause severe personal injury.

1. Inspect daily or after every 8 hours of operation.
2. Check exhaust system for leaks; repair immediately.
3. Check fuel system for leaks; replace worn fuel line components.
4. Check DC electrical system: battery terminals clean and tight.
5. Check mechanical condition: loose belts, fittings, leaking gaskets, hoses, damage.
6. With genset running, check gauges: oil pressure 28-64 psi; coolant 165-195°F; DC voltmeter 14-15 volts.

⚠ Do not over-tighten filter.

1. Spin off oil filter and discard.
2. Clean filter mounting surface thoroughly.
3. Apply thin film of oil to filter gasket.
4. Spin filter on until gasket just touches mounting pad.
5. Turn additional 3/4 turn. Do not over-tighten.
6. Add oil to crankcase, start set, check for leaks.
7. Shut off set, recheck oil level, add if necessary.

⚠ Battery electrolyte can cause severe eye damage and burns.

1. Exercise genset until engine at operating temperature.
2. Shut down and disconnect battery cables (negative first). Store battery in cool, dry place; trickle charge every 30 days.
3. Drain crankcase oil while warm. Replace oil filter. Refill crankcase and attach tag indicating oil viscosity.
4. Check coolant level; add if low. Test coolant mixture if freezing temperatures possible.
5. Drain sea water cooling system or protect with 50-50 anti-freeze mixture.
6. Plug exhaust outlets to prevent moisture, bugs, dirt.
7. Clean and wipe entire genset. Lightly coat parts that may rust with grease or oil.

1. Close sea cock.
2. Remove hose from water filter outlet.
3. Fill hose and pump with clean water.
4. Replace hose and open sea cock.
5. Check pump operation on start-up by observing water discharge from exhaust outlet.

⚠ Dirt or water in system will cause severe damage to injection pump and nozzles.

1. Loosen drain valve and bleed screws; remove bleed plug; collect fuel.
2. Remove filter element from head with bowl connected.
3. Clean bowl, O-ring and O-ring gland.
4. Lubricate O-ring with clean diesel fuel and place in bowl gland.
5. Tighten drain valve.
6. Spin bowl onto new element. Do not over-tighten.
7. Lubricate element and gasket, fill bowl and element with clean diesel fuel.
8. Spin bowl and element assembly onto head and hand tighten.
9. Disconnect starter solenoid lead at Faston terminal connector.
10. Depress Start switch until fuel purges at bleed screw and bleed plug opening.
11. Replace bleed plug and close bleed screw. Reconnect starter solenoid lead.

⚠ Battery electrolyte can cause severe eye damage and burns.

Tools: hydrometer

1. Remove plug from exhaust outlet, open sea cock.
2. Check tag on oil base and verify oil viscosity correct for ambient temperature.
3. Clean and check battery. Measure electrolyte specific gravity (1.260 @ 80°F [27°C]) and verify level. Charge if low.
4. Prime fuel system.
5. Connect starting battery, negative (-) cable last.
6. Remove all loads before starting genset.
7. After starting, run at no load for about 30 seconds. Then apply load of at least 50 percent rated capacity.
8. Check all gauges for normal readings.

⚠ Preheat longer than 30 seconds may damage glow plugs.

⚠ Excessive cranking can overheat starter.

1. Hold starting switch to STOP/PREHEAT for 10 to 30 seconds depending on temperature.
2. Release switch, then move to START.
3. Starter cranks and engine should start. Starter automatically disconnects when AC voltage builds.
4. If engine does not start after 30 seconds cranking, release switch, wait two minutes, repeat preheat.
5. If engine does not start on second try, check fuel supply and ensure fuel system primed.