Kubota D722B Engine Engine

• Weakness and Sleepiness
  Fix: Get out into the fresh air immediately. If symptoms persist, seek medical attention. Shut down the unit and do not operate until it has been inspected and repaired.
• Vomiting
  Fix: Get out into the fresh air immediately. If symptoms persist, seek medical attention. Shut down the unit and do not operate until it has been inspected and repaired.
• UNSTABLE OUTPUT VOLTAGE, ENGINE SPEED STABLE
  Cause: Broken wires or loose connections on voltage regulator assembly, brushes not OK
  Fix: Check wiring harness from regulator assembly to end bell, repair as required, inspect brushes, repair wiring or replace as required, replace the voltage regulator
• UNBALANCED GENERATOR OUTPUT VOLTAGE
  Cause: Load at generator terminals not removed, unbalanced output voltage still present
  Fix: Remove load at generator terminals
• OUTPUT VOLTAGE TOO HIGH OR TOO LOW
  Cause: Set AC output overloaded
  Fix: Remove part of the set load
• NO AC OUTPUT VOLTAGE AT RATED ENGINE RPM
  Cause: Load circuit breakers closed, circuit open between brush block and voltage regulator, brushes stuck in holder or not making good contact with slip rings, opens or grounds in rotor, stator, incorrect field voltage, incorrect F1 and F2 leads installed on terminals
  Fix: Locate cause of overload and correct as required, reset breaker or replace if bad, check continuity of circuit breakers and replace if necessary, check for open circuit between brush block and voltage regulator, release brushes if jammed in holder, clean slip rings if dirty, test continuity of rotor, stator, replace component if defective, test field voltage, check voltage regulator, examine brush block connections, connect brush leads to correct terminals
• Muscular Twitching
  Fix: Get out into the fresh air immediately. If symptoms persist, seek medical attention. Shut down the unit and do not operate until it has been inspected and repaired.
• Low Oil Pressure
  Cause: Oil level is low.
  Fix: Add oil to bring the level up to full mark. Inspect engine exterior for leaks and repair as necessary.
• Is engine getting fuel? Exhaust smoke should be blue-white and fuel flow steady from fuel return line.
  Cause: Incorrect fuel? See Operator’s Manual recommendations.
  Fix: Check fuel system: test fuel pump per Checkout [H], test fuel tank level, shut-off valves, fuel lines and connections, fuel filters, and injection pump. Okay? Does K12 fuel solenoid energize when S10(S12) is in Start position? Check B+ circuit through S10(S12). Test S11 per Checkout [G]. Test K12 per Checkout [F]. Check switch S10(S12) per Checkout [G]. Check heater relay per Checkout [E]. Check heater wiring.
• Is battery dead?
  Fix: Check CB8 circuit breaker. If okay, jumper battery cable B+ connection to K9 starter so-lenoid terminal. Does engine crank? With S10(S12) in Start position, is battery voltage present between K9 terminal S and ground? If K9 does not energize, test per Checkout [D] and replace if bad. Is battery voltage present at K9 solenoid terminal with S10(S12) in Start position? Check battery per Checkout [A] and recharge or replace. Check battery charger operation per Checkout [C]. Check battery cables for clean tight connections (ref. Checkout [B]). Check K9 starter so-lenoid and motor: if bad, repair or replace. Check B+ wiring to S10(S12), and between S10(S12) and K9. Check NC contacts of K16 per Checkout [E]. Replace if bad.
• Inability to Think Coherently
  Fix: Get out into the fresh air immediately. If symptoms persist, seek medical attention. Shut down the unit and do not operate until it has been inspected and repaired.
• High Exhaust Temperature
  Fix: The high exhaust temperature switch closes on temperature rise above 230° F (110° C). It closes to shut down the set if raw water flow is lost. It opens again when the temperature reaches about 190° F (88° C).
• High Coolant Temperature
  Fix: Check coolant level in the exhaust manifold after allowing the engine to cool down. Ensure pump belt is OK and has proper tension. The raw water flow at the exhaust outlet should be about 3 gal./min. (11.4 liter/min.). Also check cooling system cleanliness.
• Has control circuit breaker CB8 opened?
  Fix: Check B+ wiring for shorts to ground causing excessive current draw. If none, check control circuit breaker CB8 for improper wiring. Check fuel solenoid adjustment. Does set stop when start switch is released? Does run relay K13 energize and contacts close when generator set comes up to operating speed? Check NC contacts of K15 shutdown relay. Check diode CR12. Check for AC voltage build-up during cranking. Check engine monitors for proper operation and wiring. See engine troubleshooting data in engine service manual.
• Dizziness
  Fix: Get out into the fresh air immediately. If symptoms persist, seek medical attention. Shut down the unit and do not operate until it has been inspected and repaired.

Compiled from service & troubleshooting documentation across every generator set that uses the Kubota D722B.

Parts listed by aftermarket suppliers as fitting this engine — leads compiled from supplier catalogs; verify the exact part for your serial number.

• Bobcat 320 — Excavator
• Bobcat 322 — Excavator
• Bobcat 453 — Skid Steer Loader
• Bomag BW80AD-2 — Compactor
• Bomag BW80ADH-2 — Compactor
• Kubota B7400HSD — Tractor
• Kubota G1900 — Lawn Equipment
• Kubota G1900S — Lawn Equipment
• Kubota K008-5 — Excavator Compact
• Kubota U10-3 — Excavator
• Volvo Construction Equipment DD14S — Compactor
• Volvo Construction Equipment DD16 — Compactor

Other equipment known to use this engine, via filter-application cross-reference — useful for sourcing parts even when your exact machine isn't listed elsewhere on this page.