Diagnosing and Resolving Starting Problems on the John Deere 8875 Skid Steer

[MikePhua]

Introduction: A Tough Machine, a Tricky Start
The John Deere 8875 skid steer, built in partnership with New Holland, is a rugged and dependable machine that has served contractors, farmers, and landowners reliably for years. But even tough machines have their quirks, and one of the most persistent and frustrating issues owners report is a no-start or hard-start condition. Understanding the nature of the 8875's engine and electrical system is key to resolving these issues efficiently. This article explores the major causes, troubleshooting steps, and field-tested solutions for starting problems, with technical context and real-world anecdotes.
Understanding the Engine and Electrical System
The John Deere 8875 is powered by a Kubota V1903 diesel engine, a naturally aspirated four-cylinder powerplant. While this engine is generally reliable, it is also highly sensitive to battery voltage, ground quality, and glow plug condition—especially in cold weather.
Important system components include:

• Glow Plug System: Essential for cold starting, especially below 50°F (10°C). Failing glow plugs or relays often lead to long crank times or no start.
  
• Starter Motor and Solenoid: A weak starter or worn solenoid won’t crank effectively, particularly if there’s resistance in wiring.
  
• Neutral Safety Switch: Prevents the machine from cranking unless the controls are in the neutral position.
  
• Key Switch: Internal wear or corrosion can prevent consistent power delivery to the starter circuit.
  

These components form the core of the starting circuit and are common failure points on older 8875s.
Common Symptoms and What They Mean
No-start issues often present with patterns that point toward the root cause. Operators have reported the following:

• Complete silence when turning the key: Often a failed safety switch, key switch, or broken wire.
  
• Clicking but no crank: Typically a sign of a weak battery, corroded terminals, or a bad solenoid.
  
• Slow crank followed by no start: Common when glow plugs are dead or the battery voltage is low.
  
• Starts only when jumped: Suggests battery failure or poor alternator output.
  
• Starts intermittently: Points to a wiring issue or a failing ignition switch.
  

One user in Montana reported that his machine would crank only if he jiggled the key while holding the safety lever—a classic sign of a worn ignition switch or loose contact.
Battery and Cable Troubleshooting
The battery system is a frequent offender. Skid steers endure vibration, dirt, and cold, all of which degrade electrical integrity.
Recommended checks:

• Load Test the Battery: A battery can show 12.6 volts at rest but still fail under load. Use a proper load tester.
  
• Clean All Connections: Remove corrosion from terminals, both positive and negative. Clean the ground where the cable bolts to the frame.
  
• Inspect Cables for Internal Corrosion: Even if the insulation looks fine, the copper underneath may be green and degraded. Replace questionable cables.
  
• Use Dielectric Grease: Helps prevent future corrosion, especially at the terminals.
  

An operator in Ontario solved his no-crank issue by replacing the battery ground strap. It looked intact from the outside, but when cut open, the copper had nearly turned to powder.
Starter and Solenoid Testing
A failing starter or solenoid may click but fail to engage the flywheel or crank the engine properly.
Steps to verify:

• Jump the Starter Directly: Use a screwdriver or jumper wire to bridge the terminals on the solenoid. If the engine cranks, the issue is upstream—likely the key switch or safety circuit.
  
• Check for Voltage Drop: Use a multimeter to measure voltage at the starter when the key is turned. Less than 10 volts suggests resistance in the wiring or a weak battery.
  
• Inspect the Solenoid: If clicking is heard but no crank occurs, the solenoid may be sticking or burnt. Tap it lightly with a hammer and see if it engages.
  

A farm mechanic once shared how tapping the starter with a wrench allowed one more start, just enough to get the machine into the barn before replacing the worn solenoid.
Glow Plug System Failures
Glow plugs are critical for cold starting. Without them, diesel combustion is unreliable at low temperatures.
To test and address glow plug issues:

• Verify Power to the Glow Plugs: Use a test light or multimeter at the bus bar that connects all plugs. There should be power for 10–30 seconds after the key is turned on.
  
• Check the Relay: The glow plug relay can fail silently. Bypass it temporarily to confirm function.
  
• Test Each Glow Plug: Use an ohmmeter to measure resistance. Most working plugs should read between 0.5–2.0 ohms. Infinite resistance indicates an open circuit.
  

One northern Minnesota crew routinely replaced all glow plugs at the start of each winter season, knowing that just one failed unit could prevent the whole machine from starting in sub-zero conditions.
Neutral Safety Switch and Key Switch Issues
Safety switches are important, but they can also prevent starting if misaligned or faulty.
Important diagnostic steps:

• Bypass the Neutral Safety Switch: For testing purposes only, temporarily bypass the switch. If the machine cranks, replace or realign the switch.
  
• Inspect the Key Switch: If the switch feels loose, intermittent, or has burnt contacts, it may not send power consistently. Replacement is inexpensive and often resolves mysterious no-starts.
  

One service technician recalled a job where the machine would not crank until the owner held the key halfway between “run” and “start”—a textbook case of a worn key switch contact plate.
Starter Relay and Control Wiring
On many 8875s, the ignition sends signal to a starter relay, which then energizes the starter solenoid. If this relay fails or wiring corrodes, the starter won’t engage.
Troubleshooting steps:

• Listen for Relay Click: When the key is turned to “start,” listen for a click from the relay. Silence usually means no signal or a bad relay.
  
• Test Relay Output: Use a voltmeter on the relay output terminal while turning the key. If no power is present, replace the relay or trace wiring backward.
  
• Inspect Fuses and Connectors: A loose connector at the relay block or a blown fuse can cause starting failure.
  

A case from Iowa involved a relay socket that had backed out of the fuse panel due to vibration, causing intermittent starting. Securing the connector fixed the issue permanently.
Cold Weather Considerations
Temperature greatly affects diesel engine starting. The colder it is, the harder it becomes.
Cold weather tips:

• Use Engine Block Heaters: Pre-warming the engine significantly improves starting and reduces wear.
  
• Store Indoors When Possible: A garage or barn can raise ambient temps enough to make a difference.
  
• Use Diesel Additives: Prevent fuel gelling with anti-gel agents. Gelled fuel will prevent combustion no matter how strong your electrical system is.
  
• Keep Batteries Warm: A cold battery loses up to 60% of its cranking power. Battery warmers or insulated covers are useful in harsh climates.
  

In Alaska, operators often leave machines plugged in overnight using timers to cycle heaters for a few hours before the morning shift.
Preventive Maintenance to Avoid Future Issues
Long-term reliability comes from proactive care. For the 8875, this includes:

• Regularly Check and Clean Battery Terminals
  
• Replace Glow Plugs Every 1–2 Years in Cold Regions
  
• Keep Cables and Grounds in Top Condition
  
• Inspect the Starter Every 1,000 Hours or If Cranking Slows
  
• Replace Key Switches at the First Sign of Intermittency
  
• Test and Clean Relay Connections During Annual Service
  

A small investment in maintenance pays off—especially when a snowstorm hits, and your machine needs to fire up without hesitation.
Conclusion: Persistence and Patience Pay Off
The John Deere 8875 is a capable and battle-tested skid steer, but like any older machine, it demands attention to detail when things go wrong. Most starting problems are electrical in nature and can be solved with methodical troubleshooting: starting at the battery and working through to the solenoid, glow plugs, and switches. For those willing to dig into the wiring harness, test voltages, and think like a detective, reliable cold starts and consistent performance are entirely achievable—even on the chilliest mornings.