Troubleshooting Fuel Solenoid Issues on the Bobcat 773G Skid Steer

[MikePhua]

The Bobcat 773G skid steer is a versatile piece of equipment used in a variety of industries, from construction to landscaping. However, like any heavy machinery, it is prone to occasional issues that can interrupt its operation. One of the more common problems that operators face is a fuel solenoid failure, which can prevent the engine from starting or cause it to stall unexpectedly. Understanding the role of the fuel solenoid and knowing how to troubleshoot and fix this issue is critical for getting your machine back in working condition quickly.
Understanding the Fuel Solenoid in the Bobcat 773G
The fuel solenoid is an integral component of the fuel system on many diesel engines, including the one in the Bobcat 773G. It acts as an electrically-controlled valve that regulates the flow of fuel into the engine. When the ignition is turned on, the solenoid opens to allow fuel to flow to the engine. If the solenoid is malfunctioning or not working correctly, fuel flow can be restricted, which prevents the engine from starting or causes it to run erratically.
Key Functions of the Fuel Solenoid:

• Fuel Flow Control: The solenoid ensures that fuel is delivered to the engine only when it is needed, preventing fuel waste and optimizing engine performance.
  
• Start and Stop Operation: In some systems, the fuel solenoid also acts as a switch to stop the engine by cutting off the fuel supply when the operator turns off the ignition.
  

Common Symptoms of a Fuel Solenoid Problem
Fuel solenoid issues in the Bobcat 773G can present a variety of symptoms that indicate the need for inspection or repair. Here are some of the most common signs:

1. Engine Will Not Start: If the solenoid fails to open, the engine will not receive the fuel it needs to start, leaving the machine unresponsive.
   
2. Engine Stalling: A malfunctioning solenoid may intermittently cut off the fuel supply, causing the engine to stall while operating.
   
3. Lack of Power: The engine may run rough, or it may experience a lack of power if the solenoid is not regulating fuel flow properly.
   
4. No Click Sound When Ignition is Turned On: Some operators report that they hear a "click" sound when turning the key to the "on" position, which signals the solenoid opening. If there is no click, it may indicate a problem with the solenoid.
   

Possible Causes of Fuel Solenoid Issues

1. Electrical Problems
   

The fuel solenoid is electrically controlled, so any issues with the electrical connections can lead to a malfunction. Common electrical problems include:

• Corroded or Loose Wiring: Corrosion or loose connections in the wiring that powers the solenoid can prevent it from receiving the signal to open.
  
• Faulty Relay or Fuse: The fuel solenoid relies on a relay to receive power. A blown fuse or faulty relay can interrupt the power supply to the solenoid.
  • Example: A Bobcat 773G operator experienced intermittent starting issues and eventually found that the fuse controlling the fuel solenoid circuit had blown. Replacing the fuse solved the problem.
    

1. Solenoid Wear or Damage
   

Over time, the solenoid itself may wear out or become damaged. The internal components of the solenoid can degrade due to heat or excessive use, causing it to fail to open or close properly.

• Solenoid Coil Failure: If the coil inside the solenoid is damaged, it may not generate the magnetic field required to open the valve.
  
• Sticky or Jammed Solenoid: Dirt or debris may accumulate inside the solenoid, preventing it from functioning correctly.
  • Example: A mechanic working on a Bobcat 773G found that the fuel solenoid was sticking due to dirt buildup. Cleaning and lubricating the solenoid resolved the issue, allowing it to function normally.
    

1. Fuel Contamination
   

Contaminants in the fuel, such as dirt, water, or debris, can clog the solenoid or the fuel lines, preventing proper fuel flow.

• Clogged Solenoid or Fuel Lines: Over time, impurities in the fuel can block the solenoid's valve or the associated fuel lines, restricting fuel flow and causing the engine to malfunction.
  • Example: A Bobcat 773G operator had recurring fuel issues and discovered that the solenoid was clogged due to dirt in the fuel. After replacing the filter and cleaning the solenoid, the machine started running smoothly again.
    

1. Incorrect Installation or Misalignment
   

If the fuel solenoid is not installed properly or is misaligned, it may not function correctly. This could be due to improper assembly during manufacturing or a mistake during previous repairs.

• Example: A technician noted that a Bobcat 773G had trouble starting after an earlier service, only to discover that the solenoid was not properly aligned during installation, causing it to malfunction intermittently.
  

How to Troubleshoot Fuel Solenoid Issues

1. Check Electrical Connections
   

Start by inspecting the electrical connections to the fuel solenoid. Look for any loose or corroded wires and ensure that all connections are secure. If the wiring looks worn, replace it.
Tools Needed:

• Multimeter to check for voltage
  
• Wire brush or cleaner for corroded terminals
  
• Replacement wires or connectors if necessary
  

1. Test the Solenoid for Power
   

Use a multimeter to test the voltage at the solenoid’s terminals when the ignition is turned on. If there is no voltage, the problem may be with the relay, fuse, or wiring.

1. Inspect the Solenoid for Wear
   

If the electrical connections and power supply are fine, the solenoid itself may be faulty. Remove the solenoid and inspect it for any signs of physical damage, wear, or clogging. If it appears damaged, replace the solenoid.

1. Check the Fuel Filter and Lines
   

Inspect the fuel filter and fuel lines for clogs or contamination. If the filter is dirty, replace it. If dirt is found in the lines, clean them out to ensure the fuel system is functioning correctly.

1. Replace Faulty Components
   

If you identify any damaged parts—whether it’s the solenoid, fuse, relay, or wiring—replace them with genuine Bobcat parts to ensure compatibility and reliability.
Preventing Future Fuel Solenoid Problems
Preventative maintenance is key to avoiding fuel solenoid issues in the future. Regularly check and clean the solenoid, inspect the wiring, and replace the fuel filter at recommended intervals. Additionally, always use clean, high-quality fuel to reduce the risk of contamination in the system.
Additional Tips for Maintenance:

• Fuel Additives: Consider using fuel additives that prevent water accumulation and reduce the chances of clogging.
  
• Routine Inspections: During your regular machine inspections, pay particular attention to the electrical components and fuel system to catch problems early.
  

Conclusion
Fuel solenoid issues in the Bobcat 773G can cause frustrating problems with starting and engine performance. By understanding the role of the solenoid and being able to diagnose common electrical, fuel, and mechanical problems, operators can effectively troubleshoot and resolve these issues. Regular maintenance and inspections will help prevent solenoid failures and ensure that your skid steer remains in optimal working condition. Whether it’s cleaning the solenoid, replacing faulty wiring, or addressing fuel contamination, taking the time to maintain your fuel system can save time and money in the long run, minimizing downtime and maximizing productivity.