Bobcat 773 C-Series 1997 Won't Shut Off: Troubleshooting and Solutions

[MikePhua]

When dealing with issues related to the Bobcat 773 C-Series 1997 skid steer loader, one common problem that some operators face is the machine not shutting off properly. This issue can be frustrating, especially when you need to power down the equipment after a day of operation. Here’s an overview of potential causes for this problem, along with some troubleshooting tips to help resolve it.
Common Causes of the Issue

1. Fuel Solenoid Problems:
   • One of the most common reasons for the machine not turning off is a malfunctioning fuel shutoff solenoid. The fuel solenoid controls the flow of fuel to the engine, and if it fails, the engine will continue to run even after the ignition is turned off.
     
   • This could be caused by a faulty solenoid, poor electrical connections, or a problem with the solenoid’s wiring. If the solenoid isn’t receiving the proper signal to close, the engine will keep running.
     
2. Ignition Switch Failure:
   • Another potential cause is an issue with the ignition switch itself. Over time, the switch can wear out or fail to fully disconnect the electrical connection needed to shut off the engine.
     
   • If the switch is malfunctioning, it may not be sending the proper signal to the fuel solenoid or engine control unit (ECU) to cut off the power.
     
3. Electrical Wiring or Connection Issues:
   • Faulty wiring or loose connections between the ignition switch, fuel solenoid, and ECU could also contribute to this issue. Corrosion, wear, or damage to the wiring can interfere with the communication needed to turn the machine off.
     
   • A thorough inspection of the wiring and connectors should be performed to identify any issues.
     
4. Hydraulic System Malfunction:
   • In some cases, the hydraulic system or hydraulic shutoff valves may be responsible for keeping the engine running. If there’s a malfunction in the hydraulic system, such as a sticking valve or pressure buildup, it can cause the engine to stay on after the ignition is turned off.
     

Troubleshooting Steps

1. Check the Fuel Solenoid:
   • Begin by inspecting the fuel solenoid for any signs of damage or wear. Ensure that the solenoid is properly connected and receiving the correct voltage. If the solenoid is faulty, replacing it may be necessary to resolve the issue.
     
2. Inspect the Ignition Switch:
   • If the fuel solenoid appears to be functioning correctly, check the ignition switch for signs of wear or failure. Test the switch by observing whether it properly connects and disconnects when turned. If the ignition switch is found to be defective, it should be replaced.
     
3. Examine the Electrical Connections:
   • Inspect all the wiring between the ignition switch, fuel solenoid, and ECU. Look for loose, corroded, or damaged connections that could be preventing proper communication. Clean and secure any connections, and replace any damaged wires.
     
4. Evaluate the Hydraulic System:
   • If the engine continues to run despite addressing the electrical components, check the hydraulic system. Look for any signs of issues with the hydraulic valves, filters, or hoses. If hydraulic pressure is preventing the engine from shutting off, it may be necessary to service the hydraulic components.
     
5. Perform a System Reset:
   • In some cases, the issue might be resolved by performing a system reset. Disconnect the battery for a few minutes, then reconnect it and try to start the machine again. This can help reset the ECU and potentially clear any faults preventing the engine from shutting down.
     

Preventive Maintenance Tips

1. Regularly Inspect the Fuel System:
   • To prevent future issues, it's essential to regularly inspect the fuel system, including the fuel solenoid. Clean and replace parts as necessary to ensure the system functions properly.
     
2. Maintain the Ignition Switch:
   • Ensure that the ignition switch is periodically tested and cleaned. If any signs of wear appear, replace the switch promptly to avoid disruptions in operation.
     
3. Check Electrical Connections:
   • Regularly check the electrical wiring and connectors for corrosion or wear. Keep connections clean and secure to avoid issues with the electrical system.
     
4. Hydraulic System Maintenance:
   • Regularly service the hydraulic system, including checking the filters, hoses, and valves. Keeping the hydraulic components in good condition will help prevent issues related to the hydraulic shutdown system.
     

Conclusion
A Bobcat 773 C-Series 1997 that won't shut off can be a frustrating problem, but with careful troubleshooting and regular maintenance, the issue can often be resolved. By checking the fuel solenoid, ignition switch, electrical connections, and hydraulic system, you can identify and address the root cause. Regular preventive maintenance will also help avoid similar issues in the future, keeping your machine running smoothly.