Troubleshooting a Sullair 185 Compressor That Won’t Stay Running

[MikePhua]

Sullair compressors are widely used for a variety of industrial and construction applications, providing compressed air for tools, machinery, and other equipment. The Sullair 185, a portable air compressor, is particularly popular in construction settings due to its portability, efficiency, and reliability. However, like any machine, issues can arise that prevent it from running properly. One of the most common problems with the Sullair 185 compressor is when it won’t stay running. This can be frustrating and may result in significant downtime if not addressed promptly.
This article explores the potential causes of a Sullair 185 compressor not staying on, how to diagnose the problem, and practical steps to fix it.
Overview of the Sullair 185 Compressor
The Sullair 185 is a portable rotary screw compressor that provides up to 185 CFM (cubic feet per minute) of compressed air. It's often used on job sites where air-powered tools, equipment, or machinery are in constant demand. The compressor is powered by a diesel engine, making it suitable for outdoor operations without reliance on an electrical supply.
The Sullair 185 is known for its durability, ease of use, and ability to handle a variety of tasks, from powering pneumatic tools to supplying air to other industrial systems. Despite its rugged design, it can still face operational issues that prevent it from staying running, especially when it's exposed to continuous wear and environmental factors.
Common Reasons Why the Sullair 185 Won’t Stay Running

1. Fuel Supply Issues
   

One of the most common causes for a compressor shutting down unexpectedly is insufficient or inconsistent fuel supply. If the fuel filter is clogged or the fuel line is obstructed, it can prevent the diesel engine from receiving enough fuel to keep the compressor running.
Signs of fuel-related issues include:

• The compressor starts but shuts off shortly after.
  
• The engine sounds rough or sputters before stopping.
  
• Fuel gauge reading appears normal, but the compressor still shuts down.
  

Possible Causes:

• Clogged or dirty fuel filter.
  
• Air in the fuel lines.
  
• Blocked fuel line.
  
• Contaminated fuel.
  
• Faulty fuel pump.
  

1. Air Filter Clogging
   

Air filters are essential in maintaining the performance of the engine and compressor by ensuring clean air enters the system. Over time, the air filter can become clogged with dirt, dust, or debris, especially when used in dusty environments like construction sites. A clogged air filter restricts airflow, causing the engine to stall or run inefficiently.
Signs of a Clogged Air Filter:

• Compressor starts but quickly shuts down.
  
• Lack of power or performance during operation.
  
• Engine sputtering or struggling to maintain speed.
  

1. Overheating of the Compressor
   

Overheating can cause a Sullair 185 compressor to shut down as a safety precaution. The engine has built-in temperature sensors that monitor its operating temperature. If the engine gets too hot, it will automatically shut down to prevent further damage. Overheating can be caused by insufficient coolant levels, a malfunctioning thermostat, or blocked cooling fins.
Signs of Overheating:

• The compressor runs for a short time before shutting off.
  
• The engine temperature gauge reads higher than normal.
  
• Unusual engine sounds or excessive exhaust smoke.
  

1. Low Oil Pressure or Oil Contamination
   

The engine oil in the Sullair 185 serves two important functions: lubrication and cooling. If the oil pressure drops too low, the engine will shut down to prevent damage. Additionally, if the oil becomes contaminated with dirt, debris, or water, it can lead to premature engine wear or failure.
Signs of Low Oil Pressure or Oil Contamination:

• Oil pressure warning light comes on.
  
• Engine stalls or doesn’t start.
  
• Engine performance becomes erratic, with power loss or misfires.
  

1. Electrical Issues
   

Electrical problems such as a faulty ignition system, dead battery, or malfunctioning relay can prevent the compressor from staying on. A loose or corroded connection can also cause intermittent power loss, which could cause the engine to stop running unexpectedly.
Signs of Electrical Issues:

• Engine cranks but doesn’t start.
  
• Power failure or unresponsive controls.
  
• Flickering lights or non-functioning gauges.
  

1. Governor or Fuel Control Issues
   

The Sullair 185 compressor uses a governor to control the engine’s speed and regulate the amount of air delivered. If the governor or fuel control valve is malfunctioning, it can cause the engine to run erratically or stall.
Signs of Governor or Fuel Control Failure:

• Irregular engine speed or idle.
  
• Engine starts but lacks power.
  
• Sudden loss of air pressure during operation.
  

Steps to Troubleshoot the Issue

1. Check the Fuel System
   • Inspect the fuel filter and replace it if clogged or dirty.
     
   • Ensure there is no air in the fuel lines. If air is present, bleed the fuel lines to remove it.
     
   • Check for any fuel line obstructions or kinks that could be restricting fuel flow.
     
   • Examine the fuel pump and fuel tank to make sure fuel is reaching the engine without issue.
     
2. Inspect the Air Filter
   • Remove the air filter and inspect it for dirt and debris. Clean or replace the filter as needed.
     
   • Ensure that the filter is properly sealed in place to prevent unfiltered air from entering the engine.
     
3. Monitor for Overheating
   • Check the coolant level and add more if necessary.
     
   • Inspect the radiator and cooling fins for any blockages that may be preventing airflow.
     
   • Replace the thermostat if the engine is consistently running too hot.
     
4. Check Oil Pressure
   • Check the oil level and ensure it is within the recommended range.
     
   • Look for any signs of oil contamination (e.g., milky or gritty oil) and replace the oil and filter if necessary.
     
   • If the oil pressure warning light is on, check the oil pressure sensor and replace if faulty.
     
5. Inspect the Electrical System
   • Check the battery voltage and ensure the battery is fully charged.
     
   • Inspect the wiring and connections for signs of corrosion or damage.
     
   • Test the ignition system and replace faulty components such as spark plugs or the ignition coil.
     
6. Examine the Governor or Fuel Control System
   • Check for any obstructions or damage to the governor or fuel control valve.
     
   • Adjust the governor settings if necessary or replace the unit if malfunctioning.
     

Preventive Maintenance Tips

1. Regularly Replace Filters
   • Both the air and fuel filters should be inspected and replaced regularly to prevent clogging and ensure proper engine performance.
     
2. Check Fluid Levels
   • Ensure the oil, coolant, and fuel levels are maintained within the recommended ranges to avoid issues related to overheating, low pressure, or poor fuel delivery.
     
3. Inspect and Clean Cooling System
   • Periodically inspect the radiator, cooling fins, and coolant hoses for blockages, leaks, or signs of wear. Clean the cooling system to ensure proper heat dissipation.
     
4. Service the Battery and Electrical Connections
   • Keep the battery terminals clean and check for corrosion. Ensure all electrical connections are tight and free of rust to maintain a stable power supply.
     
5. Conduct Regular Operational Checks
   • Run the compressor periodically, even when not in use, to keep it in good working condition. Monitor for any unusual sounds, vibrations, or performance issues and address them promptly.
     

Conclusion
A Sullair 185 compressor that won’t stay running can be caused by several factors, from fuel and air system issues to overheating or electrical malfunctions. Identifying the root cause involves a methodical inspection of the fuel system, air filters, oil levels, electrical components, and the cooling system. Regular maintenance and timely troubleshooting will ensure that the compressor remains reliable and continues to perform optimally on the job site.