Cummins/Onan MDKUB Generator Set

⚠ High voltages within the control cabinet can cause severe personal injury or death.

Tools: voltmeter

1. Connect a voltmeter to the set output.
2. Power the set.
3. Loosen the lock nut and set the faceplate voltage adjustment trim pot to mid range.
4. Lock the pot into position by tightening the lock nut.

⚠ Disconnect starting battery positive terminal first to disable the genset before adjustments

Tools: Digital volt-ohmmeter, Frequency meter

1. Turn the generator set off and open the control box
2. Move the 60 Hz/50 Hz switch on the regulator board to the desired value
3. Remove all load and connect a frequency meter across the output
4. Loosen and back off the lock nuts on the speed adjustment screws
5. Turn the set on with no load and adjust low/high speed screws per conversion direction
6. Tighten lock nuts once target frequency is reached (53 Hz or 63 Hz stop points)
7. Center the voltage adjustment pot and adjust output voltage to rated value ± 5 VAC
8. Fine tune output voltage with the faceplate pot and recheck

⚠ Do not operate genset without belt guard in place.

⚠ Too much tension may reduce pump belt life.

Tools: finger pressure

1. Disconnect battery cables, negative first, and remove housing and belt guard.
2. Loosen bottom pivot bolt on alternator.
3. Loosen bolt through long slot in alternator mounting bracket.
4. Slide alternator until tension is right.
5. Belt tension is correct when 22 pounds (10 kg) finger pressure at middle of belt deflects it about 0.4 inch (10 mm).

⚠ Contact with high voltage can cause severe injury or death; use insulated tools and stand on a dry mat

Tools: Voltmeter, Flat-blade screwdriver

1. Attach a voltmeter securely to the L1 and L2 leads
2. Start the generator set and place a typical load on its output
3. Loosen the hex locking nut and adjust the faceplate voltage pot to correct voltage (117 VAC at 60-61 Hz for most 60 Hz applications)
4. If needed, center faceplate pot and adjust with the regulator board pot, then fine tune at the faceplate

Tools: 0-15 psi pressure gauge

1. Disconnect fuel line at pump outlet and connect a 0-15 psi pressure gauge
2. Push Start/Stop switch to START and hold until pressure stabilizes (3.5-6 psi)
3. Repeat the test with the engine running
4. If pressure is below 3.5 psi, check for restrictions or relocate pump closer to tank; replace if defective

⚠ Fuel leakage in boats presents fire and explosion hazards that can result in severe personal injury or death.

1. After installation, test the fuel system for tightness per USCG specification 33CFR183.542.
2. Any leak must be found and corrected before putting the fuel system into service.

⚠ Do not touch electrical wiring or components during testing

Tools: Volt-ohmmeter (diode check mode)

1. Stop the generator set and disconnect starting battery, negative lead first
2. Unscrew the voltage regulator from the control box
3. Disconnect the voltage regulator from the wiring harness
4. Set the volt-ohmmeter to diode check
5. Test terminal pairs per Table 6-1 and compare readings to good/bad values

1. Use the bracket as a template to locate mounting holes.
2. Allow a minimum of 2 inches (51 mm) from the top of the tank to any upper structure.
3. Mount with two 5/16 inch (8mm) bolts.
4. Use a length of hose from the kit between the radiator overflow and the dip-tube connector on the recovery tank.
5. Allow sufficient hose lengths so the tank can be easily removed from the bracket to add coolant.

Tools: drill

1. Remove the carriage bolts, nuts and washers from the drip tray.
2. Drill holes in the floor or deck in the positions indicated.
3. Use 3/8” bolts or the nearest metric equivalent to mount the generator set.

⚠ The electrical code does not allow the remote-control harness or wiring to be routed in the same conduit with AC wiring.

⚠ Be sure to seal all openings made for the wiring so exhaust or fuel vapors cannot enter the living quarters.

Tools: screwdriver

1. Unscrew the two hold-down screws that hold the panel in place.
2. Remove and discard the short 6” wiring harness connecting control panel P1 to genset J1.
3. Disconnect the leads that connect the running time meter to the terminal block inside the control box.
4. Replace the short harness with a longer harness that will reach the control panel mounting location.
5. Route the harness through the opening at the side of the control box.
6. Use the blank panel provided with the set to cover the space where the removable control panel had been.

⚠ Batteries present explosion hazard.

⚠ Battery electrolyte can cause severe eye damage and burns.

Tools: battery hydrometer, terminal puller tool

1. Keep battery case clean and dry.
2. Make certain cable connections are clean and tight; remove corrosion with ammonia solution or baking soda solution.
3. Identify positive and negative cables before making connections; connect negative cable last.
4. Maintain electrolyte level by adding distilled water to split-level marker in each cell.
5. Check specific gravity with hydrometer; charge if less than 1.215; stop charging at 1.260 at approximately 80°F (27°C).

⚠ Carbon deposits from prolonged no-load running can clog injectors, glaze cylinder walls, and stick piston rings and valves

1. Drain crankcase oil after the first 35 hours of operation
2. Minimize unloaded running time during break-in; connect an electrical load if extended running is required