The Onan 5500 generator is a popular choice for RVs, providing reliable power for various appliances and systems on the go. However, like any generator, it can encounter issues that require troubleshooting to ensure optimal performance.

In this article, we will explore common problems that Onan 5500 generators may face and provide generator troubleshooting techniques to help you resolve them effectively.

onan 5500 generator troubleshooting

Understanding the Onan 5500 Generator:

The Onan 5500 generator is a compact and powerful unit designed specifically for recreational vehicles. It features a robust engine, an alternator, a fuel system, a control panel, and various sensors to monitor its operation. Understanding the key components of the generator is essential for troubleshooting potential issues.

Common Onan 5500 Generator Issues and Troubleshooting:

  1. Failure to Start: If your Onan 5500 generator refuses to start, several factors could be at play. Begin by checking the fuel supply and ensuring that the fuel shutoff valve is open. If the fuel system is functioning correctly, inspect the spark plug for signs of wear or damage. Clean or replace the spark plug as necessary. Additionally, check the battery charge and connections to ensure they are secure.
  2. Low Power Output: A common issue with generators is a low power output, which can result in inadequate performance of appliances and systems. If you notice reduced power from your Onan 5500 generator, examine the voltage regulator settings to ensure they are properly calibrated. Inspect the wiring connections for any loose or damaged wires that may hinder power transmission. Additionally, consider checking the condition of the air filters and cleaning or replacing them if necessary.
  3. Overheating: Generators can overheat due to prolonged usage or insufficient airflow. If your Onan 5500 generator shuts down due to overheating, inspect the cooling system for any obstructions, such as debris or dirt. Clean the radiator and ensure proper ventilation to prevent overheating. If operating the generator under heavy loads, consider reducing the load to prevent excessive heat buildup.
  4. Faulty Control Panel: The control panel of the Onan 5500 generator allows you to monitor and control its operation. If you experience issues with the control panel, such as unresponsive buttons or inaccurate readings, inspect the connections and wiring for any loose or damaged components. Consider consulting the generator’s manual for troubleshooting steps specific to the control panel.
  5. Fuel System Problems: Issues within the fuel system can significantly impact the performance of the Onan 5500 generator. Check the fuel lines for any leaks or blockages and ensure that the fuel filter is clean and not clogged. Inspect the fuel pump for proper operation and listen for any abnormal sounds. If necessary, consult a professional to diagnose and repair complex fuel system problems.


Troubleshooting the Onan 5500 generator is crucial for maintaining its reliable performance. By understanding the key components and familiarizing yourself with common issues, you can effectively diagnose and resolve problems. Regular maintenance, such as checking the fuel supply, inspecting the spark plug, and ensuring proper ventilation, can prevent many issues from occurring.

In summary, troubleshooting the Onan 5500 generator involves addressing starting issues, power output problems, overheating, control panel malfunctions, and fuel system complications.

By following the recommended troubleshooting techniques outlined in this article, you can keep your Onan 5500 generator running smoothly, providing reliable power for your RV adventures.