Cummins/Onan 500 DFX-57R Generator Set

⚠ Be prepared to assume manual control if adjustments are incorrect

Tools: screwdriver

1. Remove four screws and cover from governor controller
2. Disconnect wire from TB11-22 to disconnect starter solenoid
3. Place Run-Stop-Remote switch to RUN; governor should stay at minimum fuel position
4. Return switch to STOP and reconnect wire at TB11-22
5. Position speed control rheostat to midrange (out 5 turns from low rpm)
6. Adjust speed reference potentiometer counterclockwise four complete turns
7. Start engine; adjust speed reference potentiometer clockwise/counterclockwise to reach correct rpm
8. Adjust gain potentiometer clockwise then counterclockwise until stable and responsive
9. Load and unload engine several times to confirm gain adjustment
10. Shut down and restart engine to confirm no overspeed
11. Replace governor control box cover

⚠ Generator support must be aligned to prevent premature bearing failure, vibration, drive disc failure

Tools: feeler gauge

1. Set unit on mounting foundation with vibration isolators between skid base and foundation
2. Secure skid base to isolators and isolators to foundation
3. Remove two mounting bolts and use as jackscrews
4. Raise generator and remove shims from between generator and support and skid base
5. Adjust jackscrew tension and allow generator to hang free
6. Measure clearance from skid base top to each generator support surface with feeler gauge
7. Add 0.010 in (0.254mm) to each side to determine shim amount
8. Turn jackscrews to allow clearance for placing shims
9. Lower generator onto shims using jackscrews
10. Recheck total clearance equals base-to-support clearance plus 0.010 in
11. Remove jackscrews and reinstall as mounting bolts through support, shims, and skid base
12. Secure and lock mounting bolts in place

⚠ For storage beyond six months refer to Cummins Service manual

Tools: tape

1. Start and operate engine until thoroughly warm; disconnect fuel lines to filter and injector drain line
2. Start engine on diesel fuel, then switch to preservative oil and run 5-10 minutes, stop engine and reconnect fuel lines
3. Drain oil sump, fuel filters and fuel tank, reinstall drain plugs
4. Disconnect electrical wiring, turn fuel pump shutoff valve fully counterclockwise, spray lubricating oil into intake manifold while cranking slowly
5. Cover all openings with tape
6. Drain coolant unless permanent antifreeze with rust inhibitor is used
7. Store engine in dry, uniform temperature area
8. Bar engine crankshaft two or three revolutions every three to four weeks

⚠ Do not smoke while servicing batteries - explosive gases emitted

1. Clean accumulated dirt from exterior, remove covers, tape and wrappings
2. Use suitable cleaner to remove rust preventive compound from unpainted surfaces
3. Refill crankcase with clean lubricating oil; flush and fill cooling system
4. Check coolant level, adjust or refill as necessary
5. Connect batteries
6. Verify no loads are connected to generator
7. Perform prestart servicing and start engine
8. Apply load to at least 50 percent of rated capacity
9. Check all gauges read correctly

Tools: hand or motor-driven priming pump

1. Remove oil inlet line from turbo-charger housing, fill bearing housing with clean oil, replace line, repeat for second turbo
2. Fill crankcase to L (low) mark on dipstick
3. Remove plug from head of oil filter housing and connect priming pump from clean lubricating oil source
4. Prime until 30 psi (207 kPa) pressure is obtained
5. Disconnect wire from fuel solenoid valve, close throttle, crank engine maintaining 15 psi (103 kPa) external prime for 15 seconds
6. Remove external priming equipment, replace plug in filter housing, torque 15-20 lb-ft (20-27 N.m)
7. Reconnect wire to fuel shut-off valve
8. Complete oil fill to H (high) mark on dipstick