Onan 5500 Generator Troubleshooting Manual: Expert Tips

For accurate troubleshooting of the Onan 5500 generator, refer to the Onan Generator Troubleshooting Manual. This manual provides step-by-step instructions to address common issues and resolve them effectively.

It covers various areas such as fuel, oil, carburetor, and components like the oil pressure switch and fuel filter. Additionally, it explains how to interpret fault codes and reset the circuit breaker. Following this manual can help you easily identify and resolve problems with your Onan 5500 generator.

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Common Issues And Solutions

Fuel In The Carburetor Float Bowl

One common issue with the Onan 5500 generator is fuel accumulating in the carburetor float bowl. This can lead to difficulty starting the generator or even cause it to stop running. To troubleshoot this issue, follow these steps:

  1. Turn off the generator and disconnect the spark plug wire for safety.
  2. Locate the carburetor and remove the float bowl.
  3. Inspect the float bowl for any signs of fuel. If fuel is present, clean the bowl thoroughly using carburetor cleaner.
  4. Check the float needle and seat for any debris or damage. Clean or replace if necessary.
  5. Reassemble the float bowl and start the generator to see if the issue is resolved.

If the problem persists, it may be necessary to consult the Onan 5500 generator troubleshooting manual for further guidance.

Overfull Oil Tank

Having an overfull oil tank can also cause issues with the Onan 5500 generator. If the oil level is too high, it can result in engine damage and even prevent the generator from starting. To address this problem, follow these steps:

  1. Turn off the generator and disconnect the spark plug wire.
  2. Check the oil level using the dipstick. If the oil is over the recommended level, drain some oil until it reaches the appropriate mark.
  3. Make sure to use the recommended type and grade of oil for the generator.
  4. Reconnect the spark plug wire and start the generator to see if the issue is resolved.


Proper maintenance of the oil in the Onan 5500 generator is essential for its smooth operation. Regularly checking and changing the oil can help prevent issues such as engine damage and decreased performance. Follow the steps below to troubleshoot oil-related problems:

  1. Check the oil level using the dipstick. If it is low, add the recommended type and grade of oil to bring it to the appropriate level.
  2. Inspect the oil for any signs of contamination or discoloration. If necessary, change the oil and replace the oil filter.
  3. Ensure that the oil cap and dipstick are tightly secured to prevent leaks.
  4. Start the generator and monitor for any abnormal oil pressure or noise.


A common problem with generators is issues with fuel supply. If the Onan 5500 generator is not getting enough or the proper type of fuel, it may not start or run smoothly. Troubleshoot fuel-related issues using the following steps:

  1. Check the fuel tank to ensure it has enough fuel. If necessary, add fuel to the tank.
  2. Verify that the fuel valve is open and allowing fuel to flow to the carburetor.
  3. If the fuel has been sitting for a while, consider draining and replacing it to prevent any contamination.
  4. Inspect the fuel lines for any cracks or leaks. Replace it if necessary.


The carburetor plays a crucial role in the proper functioning of the Onan 5500 generator. If the carburetor is dirty or damaged, it can cause starting and running issues. Follow these troubleshooting steps to address carburetor problems:

  1. Turn off the generator and disconnect the spark plug wire.
  2. Remove the carburetor and clean it thoroughly using a carburetor cleaner.
  3. Inspect the carburetor for any signs of damage, such as worn gaskets or clogged jets. Replace any damaged components.
  4. Reassemble the carburetor and reinstall it on the generator.
  5. Start the generator to see if the carburetor issue has been resolved.

By following these troubleshooting steps for common issues with the Onan 5500 generator, you can ensure smooth operation and reliable power generation. However, if the problems persist, consulting the Onan 5500 generator troubleshooting manual can provide more in-depth guidance.

Additional Troubleshooting Steps And Tips

Additional Troubleshooting Steps and Tips

If you’re still experiencing issues with your Onan 5500 generator, there are a few additional troubleshooting steps you can try before seeking professional help. These steps can help identify common problems and potentially solve the issue without any major repairs or replacements being necessary.

Disconnect The Oil Pressure Switch

If your generator is not starting or has intermittent starting problems, one possible cause could be a faulty oil pressure switch. This switch is designed to shut off the generator if the oil pressure drops too low, preventing damage to the engine. However, sometimes the switch can malfunction and prevent the generator from starting, even if the oil pressure is sufficient.

To test if the oil pressure switch is causing the issue, follow these steps:

  1. Locate the oil pressure switch on your generator.
  2. Disconnect the wire connected to the switch.
  3. Attempt to start the generator.
  4. If the generator starts successfully, the oil pressure switch may be faulty and should be replaced.

Replace The Fuel Filter

A clogged fuel filter can restrict the flow of fuel to the carburetor, causing starting and performance issues with your generator. If you’ve already checked and ensured that there is fuel in the tank, but the generator still won’t start or is sputtering, replacing the fuel filter might solve the problem.

Follow these steps to replace the fuel filter:

  1. Locate the fuel filter on your generator.
  2. Disconnect any fuel lines connected to the filter.
  3. Remove the old filter and replace it with a new one.
  4. Reconnect the fuel lines.
  5. Attempt to start the generator to see if the issue is resolved.

Prime The Carburetor

If your generator has been sitting for a while or has run out of fuel, it may require priming the carburetor before it will start again. Priming the carburetor helps to remove air bubbles and ensure a smooth fuel supply to the engine.

Follow these steps to prime the carburetor:

  1. Locate the primer button or primer bulb on your generator’s carburetor.
  2. Press and release the primer button or bulb several times to draw fuel into the carburetor.
  3. Attempt to start the generator.
  4. If the generator starts, allow it to run for a few minutes to ensure smooth operation.

By following these additional troubleshooting steps and tips, you can potentially resolve common issues with your Onan 5500 Generator, saving both time and money. However, if the problem persists, it is recommended to consult the Onan troubleshooting manual or seek professional assistance for further diagnosis and repair.

Service Fault Codes And Resetting

To successfully troubleshoot and resolve any issues with your Onan 5500 generator, it is important to understand the service fault codes and how to properly reset the circuit breaker. This section will provide you with the necessary information to effectively diagnose and fix any problems that may arise.

Understanding Service Fault Codes

When your Onan 5500 generator encounters a problem, it will generate a service fault code to help you identify the issue. These fault codes are essential diagnostic tools that provide information on the nature of the problem. To view the fault codes on your generator, follow these steps:

  1. Press the Stop button once.
  2. Observe the two-digit, second-level fault code as it blinks. Each blink represents a different fault code.
  3. Note down the fault code and refer to the Onan Service Manual to find detailed information on the specific fault and how to resolve it.

Understanding the fault code is the first step to effective troubleshooting. By knowing the exact issue, you can employ the appropriate troubleshooting techniques and save time in identifying the root cause.

Resetting The Circuit Breaker

In some cases, resetting the circuit breaker can resolve issues with your Onan 5500 generator. The circuit breaker acts as a safety measure and can trip if it detects a fault or overload. Follow these steps to reset the circuit breaker:

  1. Locate the circuit breaker panel on your generator.
  2. Identify the circuit breaker that has tripped. This is typically indicated by a lever that is in the “off” position or positioned differently from the others.
  3. Push the tripped circuit breaker to the “off” position and then back to the “on” position. You should feel a click as it resets.
  4. Check if the issue has been resolved. If not, refer to the Onan Service Manual or contact a professional technician for further assistance.

Resetting the circuit breaker can clear any temporary faults or overloads that may have caused the tripping. However, if the problem persists after resetting, it is important to consult the appropriate resources or seek professional help to avoid further damage to the generator.

Helpful Resources

Onan Generator Troubleshooting And Repair (YouTube)

If you’re facing issues with your Onan 5500 generator, look no further than this comprehensive YouTube video guide on troubleshooting and repair. The video, created by Randall Wingett, offers step-by-step instructions on how to address common problems such as fuel in the carburetor float bowl, an overfull oil tank, and issues with the fuel and carburetor. Each troubleshooting method is demonstrated, making it easy for you to follow along and solve the problem in no time.

Flight Systems Onan Generator Parts

When it comes to obtaining high-quality parts for your Onan generator, Flight Systems is the go-to source. Flight Systems offers a wide range of genuine Onan generator parts that are designed to meet the highest standards of quality and reliability. Whether you need a new fuel filter, oil pressure switch, or carburetor cleaner, Flight Systems has you covered. With their extensive inventory and expert knowledge, you can trust that you’ll find the right parts to keep your Onan generator running smoothly.

Rv Generator Troubleshooting Guide (pdf)

Are you in need of a comprehensive troubleshooting guide for your RV generator? Look no further than this downloadable PDF guide from Flight Systems. This guide covers a wide range of troubleshooting scenarios, providing detailed explanations and solutions for each issue. It’s important to note that this guide does not cover engine maintenance and repair procedures. For this information, please refer to the applicable Onan Service Manual. With the RV Generator Troubleshooting Guide from Flight Systems, you’ll have all the information you need to quickly diagnose and resolve any generator-related problems that may arise during your travels.

Onan Manual (pdf)

If you’re looking for a detailed manual to assist you in troubleshooting and repairing your Onan 5500 Generator, the Onan Manual in PDF format is just what you need. This 18-page manual provides comprehensive information on the operation, maintenance, and troubleshooting of your generator. From checking the engine oil level to keeping battery connections clean and tight, this manual covers all the essential steps to ensure the proper functioning of your Onan generator. With the Onan Manual in hand, you’ll be equipped with the knowledge to tackle any issues that may arise and keep your generator in optimal condition.

Frequently Asked Questions

What Does 3 Flashes Mean On An Onan Generator?

Three flashes on an Onan generator indicate a service fault. Press the Stop button once to see the two-digit fault code.

How Do I Reset My Onan 5500 Generator?

To reset your Onan 5500 generator, follow these steps: 1. Disconnect the oil pressure switch. 2. Replace the fuel filter. 3. Prime the carburetor. 4. Press STOP once to make the fault code blink. 5. Press STOP again to reset the generator.

Why won’t my RV generator start just by clicking?

If your RV generator just clicks and won’t start, check for fuel in the carburetor float bowl, an over-full oil tank, low oil levels, fuel issues, or a dirty carburetor. Disconnect the oil pressure switch, replace the fuel filter, and prime the carburetor as troubleshooting steps.

How Long Do You Prime An Onan 5500 Generator?

To prime an Onan 5500 generator, disconnect the oil pressure switch, replace the fuel filter, prime the carburetor, and ensure all connections are secure. The generator should be ready to start after following these steps.

How do I troubleshoot my Onan 5500 generator?

To troubleshoot your Onan 5500 generator, start by checking the fuel and oil levels, inspecting the carburetor, and cleaning the carburetor float bowl. Additionally, replace the fuel filter and prime the carburetor if needed.


To troubleshoot your Onan 5500 generator, follow the steps provided in the Onan Generator Troubleshooting Manual. It covers various issues such as fuel problems, overfull oil tanks, carburetor concerns, and more. Remember to check the fault codes and follow the instructions for corrective action.

Regular maintenance, such as monitoring oil levels and keeping battery connections clean, is also crucial for optimal generator performance. For more specific troubleshooting guides, refer to the Onan RV generator manual or consult a professional.

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