Restoring and Maintaining the Bobcat 743B: A Skid Steer That Still Earns Its Keep

[MikePhua]

Introduction: The Legacy of the 743B Bobcat
The Bobcat 743B is a classic skid steer loader that represents the rugged reliability of late 20th-century construction equipment. Produced in the late 1980s and early 1990s, this model gained popularity for its simplicity, mechanical resilience, and versatility on the job site. Although newer machines boast advanced hydraulics and electronic systems, many contractors, farmers, and property owners continue to rely on the 743B for its straightforward maintenance and surprising capability.
Keeping a 743B in good working condition does, however, require attention to a few known quirks—particularly in the electrical system, fuel delivery, and hydraulic functions. Understanding these systems and how to address common issues allows owners to get maximum value from these durable machines.
Basic Specifications of the Bobcat 743B

• Engine: 36-hp Kubota V1702 diesel engine
  
• Operating Weight: Approximately 4,800 lbs (2,177 kg)
  
• Rated Operating Capacity: 1,300 lbs (590 kg)
  
• Hydraulic Pump Flow: Around 11 GPM (gallons per minute)
  
• Lift Path: Radius lift design
  
• Controls: Hand levers for drive, foot pedals for loader operation
  

These specs made the 743B ideal for landscaping, light construction, small demolition, and agricultural tasks.
Common Issues and Solutions
Despite its strengths, the 743B is not immune to age-related challenges. The most commonly reported areas of concern include:

• Fuel System Problems
  • Hard starts, engine stalling, or surging can result from clogged fuel filters or degraded fuel lines.
    
  • Water in the fuel or worn injectors can also affect performance.
    
  Solution: Replace fuel filters regularly and drain water separators. Ensure fuel hoses are not cracked or leaking. Periodically check and clean the fuel tank of sediment.
  
• Glow Plug and Starting Issues
  • Cold-weather starting problems often trace back to faulty glow plugs or the glow plug relay.
    
  • A malfunctioning timer can also prevent the system from warming the engine properly.
    
  Solution: Test glow plugs individually using a multimeter. Replace the relay and timer if glow plugs are not receiving power.
  
• Charging System Defects
  • A common issue involves dead batteries due to failed alternators or voltage regulators.
    
  • Dim or flickering lights can signal trouble before the battery fully drains.
    
  Solution: Verify alternator output with a voltmeter. A healthy system should read around 13.5–14.5 volts at idle. If not, consider replacing the alternator or regulator.
  
• Hydraulic Leaks or Sluggishness
  • Slow response or weak lifting capacity often results from dirty hydraulic oil or a clogged filter.
    
  • Leaks around the control valve or lift cylinders are also frequent with age.
    
  Solution: Change hydraulic oil and filter at regular intervals. Inspect hoses and seals for wear. Cylinder rebuild kits are widely available.
  
• Electrical Harness Degradation
  • Crumbling insulation and broken connectors can interrupt key circuits.
    
  • Older models used minimal protection against moisture or rodent damage.
    
  Solution: Rewire critical components using marine-grade wire and sealed connectors. Add a fuse block or relays for improved reliability.
  

Restoration Tips and Parts Sourcing
Many 743B units still operate in rough conditions thanks to DIY restoration efforts and the abundance of aftermarket support. Here are some tips for a successful rebuild:

• Wiring Harness: If your harness is severely damaged, consider building a custom one. Use color-coded diagrams or label wires during disassembly.
  
• Parts Suppliers: Bobcat dealers can supply OEM parts, but aftermarket providers like Skid Steer Solutions, Loader Parts Source, and All States Ag Parts often offer cheaper alternatives.
  
• Manuals: Operator and service manuals are crucial for torque specs, wiring diagrams, and hydraulic routing. Digital versions are often available online.
  

Terminology Explained

• Glow Plug: A heating element used in diesel engines to pre-warm the combustion chamber for easier starting.
  
• Lift Path: Refers to the motion arc of the loader arms—radius lift paths swing out and up, while vertical lift paths rise straight.
  
• Rated Operating Capacity (ROC): The maximum safe load that the loader can lift without compromising stability.
  
• Hydraulic Flow (GPM): The amount of hydraulic fluid delivered per minute, affecting the speed and power of attachments.
  

Real-World Story: A Skid Steer That Survived the Flood
In 2011, a rural town in the Midwest faced record-breaking floods. A farmer’s 743B Bobcat, parked in a barn, was submerged for days. After draining the fluids, cleaning electrical connectors, and rebuilding the starter, the machine fired back up. With a makeshift grapple, it cleared debris from roads and fields for weeks before power and machinery returned. That 743B became a symbol of resilience, earning the nickname “Ol’ Mudpuppy.”
Why the 743B Still Matters Today
With low operating costs, easy-to-understand mechanics, and a robust Kubota diesel engine, the 743B continues to prove its worth. While newer machines have more power and features, they often come at the cost of complexity and high repair bills. For owner-operators and small outfits, the 743B remains an ideal choice for tight budgets and tough jobs.
Conclusion
The Bobcat 743B may be considered a relic by some, but for those who own one—and keep it maintained—it’s a machine that refuses to quit. Through practical maintenance, a bit of ingenuity, and support from parts suppliers, this skid steer can keep working well into its fourth or fifth decade. Whether you're restoring one for daily use or occasional chores, the 743B is proof that solid design never goes out of style.