Ford SG875 Engine

• Engine will not crank
  Cause: Fault lamp on
  Fix: Correct fault and reset control
• SWITCH OFF lamp flashes
  Cause: Run/Stop/Remote switch is in the STOP position which will prevent automatic starting if an automatic transfer switch is used
  Fix: Move the Run/Stop/Remote switch to the REMOTE position for automatic starting
• OVERCRANK lamp lights and engine stops cranking
  Cause: Possible fuel or ignition system problem
  Fix: Check for empty fuel tank, fuel leaks, or plugged fuel lines and correct as required; check for dirty fuel filter and replace if necessary (see Maintenance section); check for dirty or plugged air filter and replace if necessary (see Maintenance section); check for loose connections in the ignition primary, ignition secondary, or solenoid valve circuits and correct as required; reset the control and restart after correcting the problem; contact an Onan dealer or distributor for service if none of the above
• Engine runs and then shuts down, OVERSPEED lamp lights
  Cause: Engine has exceeded normal operating speed
  Fix: Contact an Onan dealer or distributor for service
• Will not crank. Engine
  Fix: Indicates possible fault with control or starting system. Check for the following conditions: a. Fault lamp on. Correct fault and reset control. b. Poor battery cable connections ... Clean the battery cable terminals and tighten all connections. c. Discharged or defective
• The standard undesignated fault functions are lights; Engine shuts down immediately, engine runs for several seconds and then shuts down, or engine continues to run. FAULT 1 or FAULT 2
• Remote circuit breaker is tripped. Engine starts from generator control panel but will not start automatically or from a remote panel (Note: Run/Stop/Remote switch must be in the REMOTE position for automatic or remote starting)
  Cause: Remote circuit breaker is tripped
  Fix: Reset breaker and restart; contact an Onan dealer or distributor if breaker trips after resetting
• Remote circuit breaker is tripped. Remote circuit breaker
  Fix: Reset breaker but will not start automatically or from a remote panel (Note: Run/Stop/Remote switch must be in the REMOTE position for automatic or remote starting). Contact an Onan dealer or distributor if breaker trips after resetting.
• PRE LO OIL PRES lamp lights. Engine continues to operate. PRE LO OIL PRES
  Fix: Indicates engine oil pressure has dropped to 20 psi (138 kPa). If engine can be stopped, follow procedures in step 5. If generator is powering critical loads and cannot be shut down, wait until next shutdown period and then follow step 5 procedure.
• PRE LO OIL PRES lamp lights. Engine continues to operate
  Cause: Engine oil pressure has dropped to 20 psi (138 kPa)
  Fix: If engine can be stopped, follow procedures in step 5; if generator is powering critical loads and cannot be shut down, wait until next shutdown period and then follow step 5 procedure
• PRE HI ENGINE TEMP lamp lights. Engine continues to operate. PRE HI ENGINE TEMP
  Fix: Indicates engine has begun to overheat and engine temperature has risen to approximately 205°F (97°C). If engine can be stopped, follow the procedures in step 3. Use the following procedures if generator is powering critical loads and cannot be shut down. a. Check air inlets and outlets and remove any obstructions to airflow. b. Open doors or windows in generator area to increase ventilation. c. Reduce load if possible by turning off non-critical loads.
• PRE HI ENGINE TEMP lamp lights. Engine continues to operate
  Cause: Engine has begun to overheat and engine temperature has risen to approximately 205°F (97°C)
  Fix: If engine can be stopped, follow the procedures in step 3; if generator is powering critical loads and cannot be shut down: check air inlets and outlets and remove any obstructions to airflow; open doors or windows in generator area to increase ventilation; reduce load if possible by turning off non-critical loads
• No AC output voltage
  Cause: Field breaker is tripped
  Fix: Reset breaker; contact an Onan dealer or distributor if voltage buildup causes breaker to trip
• LO OIL PRES lamp lights. Engine shuts down. LO OIL PRES
  Fix: Indicates engine oil pressure has dropped to 14 psi (97 kPa). Check oil level and replenish if low. Reset control and restart. Contact an Onan dealer or distributor if oil pressure is not in the range of 35 to 60 psi (241 to 414 kPa) ...
• LO OIL PRES lamp lights. Engine shuts down
  Cause: Engine oil pressure has dropped to 14 psi (97 kPa)
  Fix: Check oil level and replenish if low; reset control and restart; contact an Onan dealer or distributor if oil pressure is not in the range of 35 to 60 psi (241 to 414 kPa)

Compiled from service & troubleshooting documentation across every generator set that uses the Ford SG875.

Pooled from every document that names this exact engine — confirm the interval and part number against your unit's serial number.