Bobcat 763 Cranks but Won't Start

[MikePhua]

When you face a situation where your Bobcat 763 cranks but fails to start, it can be frustrating, especially when you're unsure whether the issue lies with the engine, electrical system, or fuel system. This problem, although not uncommon, can have multiple causes, ranging from simple to more complex. In this article, we'll explore the common issues that could prevent your Bobcat 763 from starting, how to troubleshoot these problems, and what solutions are available.
Understanding the Bobcat 763 Skid Steer
The Bobcat 763 is a popular skid steer loader in the Bobcat brand's lineup, widely known for its reliability and versatility. Manufactured by Bobcat Company, which was founded in 1947, the 763 is part of the 700 series and has been a staple in the construction and landscaping industries. It's equipped with a 58-horsepower engine and features a lifting capacity of over 1,600 pounds. The 763 is used for a variety of tasks, including digging, lifting, and moving heavy materials.
Common Causes of Crank-No-Start Issue
When your Bobcat 763 turns over but fails to fire, the problem can stem from several different areas. Below are some common causes and troubleshooting tips.
1. Fuel Supply Issues
One of the first things to check when diagnosing a no-start condition is the fuel supply. If the fuel system isn't delivering fuel to the engine properly, the machine will crank but not start. Here are a few things to check:

• Fuel Filter: A clogged fuel filter can restrict fuel flow, leading to starting issues. If the fuel filter hasn't been replaced in a while, it may be time for a replacement.
  
• Fuel Lines: Check for cracks or leaks in the fuel lines. Any breaks in the fuel lines will prevent proper fuel delivery.
  
• Fuel Tank: Ensure that there is enough fuel in the tank. It sounds simple, but sometimes a low fuel level can prevent the engine from starting, especially if the fuel pump is struggling to draw fuel.
  
• Fuel Pump: If the fuel pump isn’t working properly, it will fail to send fuel to the engine. Listen for the sound of the fuel pump when you turn the key to the "on" position. If you don't hear it running, the pump may need replacement.
  

2. Electrical System Failure
The electrical system plays a vital role in starting the engine. If there's a problem with the battery or the electrical connections, the engine may crank but not fire. Here’s what you need to check:

• Battery: A weak or discharged battery is a common culprit when a machine cranks but doesn’t start. Check the battery voltage with a multimeter to make sure it has at least 12 volts. If the voltage is low, try jump-starting the machine or replacing the battery.
  
• Battery Terminals: Dirty or loose battery terminals can prevent the starter from receiving proper voltage. Clean the terminals and ensure they are tightly connected.
  
• Fuses and Relays: Check the fuses and relays related to the starting system. A blown fuse or faulty relay could prevent the engine from starting.
  
• Ignition Switch: If the ignition switch is faulty, it may not send the necessary signal to the starter motor. Testing the ignition switch can help identify any issues here.
  

3. Starter Motor and Solenoid
The starter motor is responsible for turning the engine over, and the solenoid is responsible for engaging the starter. If these components are malfunctioning, the machine may crank without starting.

• Starter Motor: A worn-out starter motor might struggle to turn the engine over, leading to intermittent starting issues. If you hear a clicking sound when you turn the key, the starter may be faulty.
  
• Solenoid: The solenoid provides the electrical connection between the battery and the starter motor. A faulty solenoid can prevent the starter from engaging. If you're hearing the starter click but the engine doesn't turn over, this could be the issue.
  

4. Fuel Injectors or Glow Plugs
For diesel engines like the one found in the Bobcat 763, a faulty glow plug or fuel injector can prevent the engine from starting.

• Glow Plugs: These are essential for starting a cold engine. If one or more glow plugs are faulty, the engine may fail to start in cold weather conditions. Test the glow plugs using an ohmmeter to check for resistance. If any of them are faulty, replacing them should resolve the issue.
  
• Fuel Injectors: Blocked or malfunctioning fuel injectors can also prevent the engine from starting. If fuel injectors are clogged, the engine won't receive the correct amount of fuel to start. Injector cleaning or replacement may be necessary.
  

5. Air Intake or Compression Problems
If the engine isn't getting enough air or there's a problem with engine compression, it may not start even if everything else seems fine.

• Air Filter: A clogged air filter can restrict airflow to the engine, making it difficult to start. Inspect and replace the air filter if necessary.
  
• Compression: Low engine compression could be the result of worn piston rings, valves, or other internal engine components. Performing a compression test can help identify issues with engine internals that may prevent it from starting.
  

6. Safety Switches and Relays
Bobcat skid steers are equipped with several safety switches that prevent the machine from starting if certain conditions aren't met. For example, the seat switch, brake switch, or neutral safety switch could be the cause if the engine fails to start.

• Seat Switch: This switch ensures that the operator is in the seat before starting the machine. If it's malfunctioning, the engine will not start.
  
• Neutral Safety Switch: If the transmission is not in neutral, the engine may not start. Check to ensure the machine is in the correct gear position.
  

Troubleshooting Steps
If your Bobcat 763 cranks but won't start, follow these troubleshooting steps to narrow down the issue:

1. Check the battery voltage and ensure that it has a charge above 12 volts. Clean the terminals and check for loose connections.
   
2. Inspect the fuel system. Verify that there’s fuel in the tank, the fuel filter is clean, and fuel lines are free from obstructions.
   
3. Check the glow plugs to ensure they are functioning properly if you're working in cold weather.
   
4. Test the starter motor by listening for clicks or by checking the voltage at the solenoid and starter motor.
   
5. Verify the air filter and clean or replace it if necessary to ensure proper air intake.
   
6. Check the safety switches to make sure the machine is in neutral and the operator is seated.
   

Conclusion
A Bobcat 763 that cranks but won’t start can be caused by several factors, including fuel delivery issues, electrical problems, starter motor failure, or malfunctioning safety switches. By methodically troubleshooting each component, you can pinpoint the issue and make the necessary repairs. Regular maintenance, such as changing fuel filters, replacing glow plugs, and inspecting the battery, can help prevent starting problems and extend the life of your Bobcat 763.