Why the John Deere G35 Mini Excavator Cranks but Won’t Start

[MikePhua]

The John Deere G35 and Its Compact Excavator Lineage
The John Deere G35 mini excavator belongs to a generation of compact machines designed for tight-access utility work, landscaping, and small-scale trenching. John Deere, founded in 1837, expanded its compact equipment offerings in the late 1990s and early 2000s to compete with brands like Kubota, Takeuchi, and Bobcat. The G35, with an operating weight around 3.5 metric tons, features a zero-tail swing design, pilot-operated hydraulics, and a diesel engine typically sourced from Yanmar or Mitsubishi.
Though not as widely distributed as the later D and G-Series models, the G35 earned a reputation for reliability and mechanical simplicity. However, like many compact machines, it’s vulnerable to electrical and fuel system faults—especially when subjected to rough terrain or inconsistent maintenance.
Cranking Without Starting Common Causes
When a mini excavator cranks but fails to start, the issue typically lies in one of three systems:

• Fuel delivery
  
• Electrical ignition
  
• Safety interlocks
  

In the reported case, the machine died after hitting a large bump and subsequently refused to start, though it continued to crank. This symptom suggests that a component was jarred loose or damaged during the impact.
Initial Diagnostic Priorities
Before diving into complex diagnostics, technicians should begin with basic checks:

• Inspect all fuses, especially those related to the fuel solenoid and ignition circuit
  
• Verify battery voltage (should be above 12.4V under load)
  
• Check fuel level and confirm that the fuel shutoff solenoid is functioning
  
• Examine wiring harnesses near the engine and under the operator platform for disconnections or abrasion
  
• Confirm that all safety switches (seat, boom lock, travel lock) are engaged properly
  

One mechanic noted that a bump strong enough to kill the engine could dislodge the fuel pickup tube inside the tank or damage the fuel solenoid wiring. These components are often mounted with minimal protection and can be affected by vibration or impact.
Fuel System Vulnerabilities
The fuel system in compact excavators relies on a lift pump (mechanical or electric), a fuel filter, and a solenoid-controlled injector system. If the pickup tube inside the tank is cracked or disconnected, the pump may draw air instead of fuel. Similarly, a clogged filter or failed solenoid will prevent fuel from reaching the combustion chamber.
Recommended steps:

• Remove the fuel line at the injector pump and check for flow during cranking
  
• Inspect the fuel filter for contamination or water intrusion
  
• Test the solenoid by applying 12V directly to confirm actuation
  
• Bleed the fuel system to remove trapped air, especially if the machine sat idle
  

A contractor in Alberta shared that his G35 refused to start after winter storage. The culprit was a cracked pickup tube that allowed air into the system. After replacing the tube and bleeding the lines, the machine started immediately.
Electrical and Safety Interlock Checks
Modern mini excavators include safety interlocks that prevent starting if certain conditions aren’t met. These may include:

• Neutral gear position
  
• Boom lock engaged
  
• Seat switch activated
  
• Travel lock disengaged
  

If any of these switches are damaged or misaligned, the ECM may block fuel delivery or ignition. Technicians should test each switch for continuity and inspect connectors for corrosion.
In one case, a machine failed to start because the seat switch had shifted slightly during transport. A simple adjustment restored function.
Impact-Related Failures and Field Anecdotes
Machines that die after hitting a bump may suffer from:

• Loose ground wires
  
• Disconnected sensor plugs
  
• Broken fuel lines or cracked fittings
  
• Dislodged relays or fuses
  

One operator recalled a similar incident where a mini excavator stalled after bouncing over a stump. The issue was traced to a loose ground strap near the starter motor. After cleaning and tightening the connection, the machine started without issue.
Another technician found that the fuel solenoid wire had been pinched between the engine and frame, shorting intermittently. Re-routing the wire and adding protective sleeving resolved the problem.
Recommendations for Owners and Operators
To prevent no-start conditions after impact or transport:

• Secure all wiring harnesses with clamps and protective sleeves
  
• Inspect fuel lines and pickup tubes annually
  
• Replace fuses with OEM-rated components only
  
• Keep a spare solenoid and fuel filter in the cab for field repairs
  
• Maintain a log of electrical and fuel system service history
  

Operators should also be trained to recognize early signs of failure—such as delayed starting, sputtering, or intermittent stalling—and report them before the machine becomes inoperable.
Conclusion
A John Deere G35 mini excavator that cranks but won’t start after a jolt likely suffers from a disrupted fuel or electrical pathway. By methodically checking fuses, solenoids, fuel flow, and safety switches, technicians can restore function without major disassembly. In compact excavation, reliability depends not just on rugged design—but on the vigilance of those who operate and maintain the machine. Even a small bump can reveal a hidden weakness, and knowing where to look makes all the difference.