Cummins/Onan WK Series Generator Set

Tools: ohmmeter

1. Remove access cover from exciter end of the generator.
2. Isolate each diode by disconnecting one end from its connection point.
3. Use an ohmmeter to measure resistance in the individual diode; reverse the ohmmeter leads and repeat.
4. A good diode should have a high resistance value one way and a low value when leads are reversed; replace if not good.
5. Check all diodes in accordance with step 3.

⚠ The generator support must be aligned to the skid base to prevent premature generator bearing failure; failure to do so could void the warranty.

Tools: feeler gauge or dial indicator, jackscrews

1. Set plant on its mounting foundation using vibration isolators; secure skid base to foundation.
2. Remove the two mounting bolts and shims securing the generator support to the skid base.
3. Use the mounting bolts as jackscrews in the threaded holes; remove tension and allow generator to hang free.
4. Measure clearance from top of skid base to each generator support mounting surface.
5. Add .035 inches to each side of the skid base; this determines the amount of shims required.
6. Turn jackscrews to allow clearance for placing shims between skid base and generator support.
7. Lower generator on shims and recheck total clearance (must equal base-to-support clearance plus .035 in.).
8. Remove jackscrews and install as mounting bolts through generator support, shims and skid base; secure and lock.

⚠ Avoid skin or clothing contact with electrolyte; dispose of it in a safe manner.

Tools: hydrometer or filler bulb

1. Fully charge the battery.
2. With battery still on charge, draw off all electrolyte above the plates in each cell; do not pour off.
3. Refill each cell with distilled water to normal level.
4. Continue charging for one hour at a 4- to 6 ampere rate.
5. Test each cell; if specific gravity is still above 1.225, repeat steps 2, 3 and 4.

1. Run plant until thoroughly warm.
2. Drain oil from oil base while still warm; refill and attach a warning tag stating oil viscosity used.
3. Remove each spark plug; pour one ounce of rust inhibitor (or SAE #50 oil) into each cylinder; install spark plug.
4. Service air cleaners as outlined in Waukesha manual.
5. Clean throttle linkage and protect by wrapping with a clean cloth.
6. Plug exhaust outlets to prevent entrance of moisture, bugs, dirt, etc.
7. Wipe entire unit; coat parts susceptible to rust with a light film of grease or oil.
8. If battery is used, disconnect and follow standard battery storage procedure.
9. Provide a suitable cover for the entire unit.

1. Press the RUN-STOP switch to its RUN position, holding in contact to crank the engine.
2. Do not crank for more than 30 seconds at one time; investigate any failure to start.
3. If engine fails to crank, check that the cranking limiter switch is closed.

1. If conditions permit, disconnect electrical load and allow the plant to run a few minutes at no load.
2. Press the RUN-STOP switch to its STOP position to stop the plant.

1. Remove the three No. 10-24 screws which fasten voltage regulator to DC alternator; remove regulator to gain access to phenolic cover, disconnecting leads as required.
2. Remove the two No. 8-32 screws on phenolic cover and lift out cover and gasket.
3. Pull brush assembly straight up and lift out.
4. For reassembly, reverse procedure.

⚠ Do not over-torque the diode.

Tools: proper size wrenches

1. Use proper size wrenches to hold the body of the diode while removing the nut attaching it to the heat sink.
2. Push the diode free of its mounting hole in the heat sink.
3. Be sure new diode is installed in the same position (direction) as defective diode; parts have directional arrows.
4. Insert new diode into its mounting hole in the heat sink.
5. Using nut and washer provided, secure diode, being careful not to allow it to turn while tightening; do not over-torque.
6. Connect leadwires to appropriate terminals.
7. Replace access cover.