Cummins/Onan 50.0 DDB 15R Generator Set

1. Rotate the external knurled knob at the rear of the injector pump housing.
2. Turning inward (clockwise) shortens the governor control spring, making it less sensitive and increasing speed droop.
3. Turning outward (counterclockwise) has the opposite effect.

1. Back off the high speed stop screw.
2. Screw in the low speed adjusting screw until the generator output frequency meter reads 60 Hz (generator on load).
3. Turn in the high speed adjusting screw until it bottoms.
4. Secure the locknuts.

⚠ Proceding instructions do not apply to models with a 347/600 voltage (designated 9X) or a 120/240 voltage (designated 3R); these connections are made at the factory.

1. Factory ships these 12 lead generators with load connection wires not connected together; wires T1 through T12 must be brought together before making load connections.
2. Remove either right, left or top panel from control box.
3. Connect wires together as shown on panel and in Figure 13 according to voltage desired.
4. Open hinged control panel doors. Connect lead from terminal 63 to correct terminal (H2, H3, H4, H5 or H6) for voltage desired.
5. Close front panel and secure with 1/4 turn fasteners.
6. Connect load wires to generator leads.

⚠ Do not smoke while servicing batteries; lead acid batteries give off explosive gases while being charged.

1. Check the condition of the starting batteries at least every two weeks.
2. See that connections are clean and tight; coat with non-conductive grease.
3. Keep electrolyte at the proper level above the plates by adding distilled water.
4. Check specific gravity; recharge if below 1.260.

⚠ Do not attempt to pour off electrolyte; avoid skin or clothing contact.

Tools: hydrometer, filler bulb

1. Fully charge the battery.
2. With the battery still on charge, draw off the electrolyte above the plates in each cell using a hydrometer or filler bulb.
3. Refill each cell with distilled water to normal level.
4. Continue charging for 1 hour at 4 to 6 amperes.
5. Test each cell; if specific gravity is still above 1.225, repeat steps 2, 3 and 4 until reduced to 1.225.

⚠ If the primer lever will not pump and no resistance is felt at upper end of stroke, turn engine over with starter to change position of fuel pump drive lobe on camshaft.

1. Verify all connections in the fuel system are secure and no leaks exist.
2. Loosen bleed plug on top of fuel filter.
3. Pump primer lever until a solid stream of fuel, free of air bubbles, flows from bleed plug.
4. Secure bleed plug.
5. Loosen inlet fuel line on injector pump.
6. Operate primer lever on fuel transfer pump until a solid stream of fuel, free of air bubbles, flows from inlet line opening.
7. Secure injector pump fuel inlet line.
8. Leave fuel transfer pump priming lever at lowest point of stroke.

⚠ When reassembling threaded aluminum parts, be sure to use anti-seize compound.

1. Remove head and valve assembly.
2. Clean foreign matter out of the tank.
3. Remove element and scrape off scale accumulated on the sheathing.

⚠ Verify electric solenoid valve for city water cooled plants is open before initial start to allow coolant chambers to fill; overheating and engine damage could result.

1. Recheck that crankcase is filled.
2. Recheck cooling system is filled and input solenoid valve open.
3. Recheck batteries are charged and connected.
4. Recheck fuel solenoid valve open.
5. Move the run-stop/reset-remote switch to the run position.
6. Immediately after start, observe oil pressure gauge; normal oil pressure is 45 to 65 psi (310.5 to 448.5 kPa).
7. Check DC ammeter (10 to 30 amperes), AC voltmeter, and frequency meter.

1. Run the engine at no load for three to five minutes to reduce and stabilize engine temperatures.
2. Move the run-stop/reset-remote switch to stop position.