Bobcat 743 Hard Starting: Troubleshooting and Solutions

[MikePhua]

The Bobcat 743, equipped with the Kubota V1702 engine, is a reliable skid-steer loader known for its durability and performance. However, like any mechanical equipment, it can experience starting difficulties, especially in colder conditions or after periods of inactivity. Understanding the common causes and implementing effective troubleshooting steps can help restore reliable starting performance.

Understanding the Starting System
The starting system of the Bobcat 743 includes several key components:

• Glow Plugs: These are essential for pre-heating the combustion chamber, ensuring efficient ignition of the diesel fuel, particularly in cold weather.
  
• Glow Plug Relay: This component controls the power supply to the glow plugs.
  
• Fuel System: Includes the fuel tank, lift pump, fuel filter, and injectors, all of which must be in good condition to ensure proper fuel delivery.
  
• Battery and Electrical Connections: A fully charged battery and clean, tight electrical connections are crucial for reliable starting.
  

Common Causes of Hard Starting

1. Faulty Glow Plugs or Relay
   A common issue with the Bobcat 743 is the failure of glow plugs or the glow plug relay. As one operator noted:
   

   "I'm getting no power to the glow plugs, but I'm getting power to the pre-heat solenoid... I think that the solenoid is gone so I'm replacing it & I will let you know how it works out!"

   If the glow plugs are not receiving power, the engine may struggle to start, especially in colder temperatures.
   
2. Clogged Fuel System
   Over time, the fuel system components can become clogged with debris or contaminants. This can lead to poor fuel delivery and starting issues. Regular maintenance, including cleaning or replacing the fuel filter, can help prevent this problem.
   
3. Weak or Faulty Battery
   A weak or faulty battery may not provide sufficient power to the starter motor, leading to slow cranking or failure to start. Ensuring the battery is fully charged and in good condition is essential for reliable starting.
   
4. Electrical Connection Issues
   Corroded or loose electrical connections can impede the flow of electricity to the starter motor and glow plugs, causing starting difficulties. Regularly inspecting and cleaning electrical connections can help maintain optimal performance.
   

Troubleshooting Steps

1. Test Glow Plugs and Relay
   • Use a multimeter to check for voltage at the glow plug terminals when the ignition is in the pre-heat position.
     
   • If no voltage is present, inspect the glow plug relay and associated wiring for faults.
     
2. Inspect Fuel System
   • Check the fuel filter for clogs and replace if necessary.
     
   • Ensure the fuel lines are free from leaks and blockages.
     
   • Bleed the fuel system to remove any air pockets that may impede fuel flow.
     
3. Check Battery and Electrical Connections
   • Test the battery voltage and replace if below the recommended level.
     
   • Inspect all battery terminals and cables for corrosion or looseness and clean or tighten as needed.
     
4. Verify Starter Motor Operation
   • Listen for any unusual sounds when attempting to start the engine, which may indicate a problem with the starter motor.
     
   • If the starter motor is suspected to be faulty, it may need to be repaired or replaced.
     

Preventive Maintenance Tips

• Regularly Inspect Glow Plugs and Relay: Check the condition and operation of glow plugs and the relay to ensure they function properly.
  
• Maintain Fuel System: Replace the fuel filter at recommended intervals and ensure the fuel system is free from contaminants.
  
• Monitor Battery Health: Regularly check the battery voltage and condition, and replace it when necessary.
  
• Clean Electrical Connections: Periodically inspect and clean all electrical connections to prevent corrosion and ensure reliable operation.
  

Conclusion
Hard starting issues with the Bobcat 743 can often be traced to problems with the glow plugs, fuel system, battery, or electrical connections. By systematically troubleshooting these components and performing regular maintenance, operators can ensure reliable starting performance and prolong the life of their equipment.
If problems persist after performing these troubleshooting steps, it may be advisable to consult with a professional mechanic or technician experienced with Bobcat equipment.