RV Generator Keeps Shutting Off? Troubleshoot Guide 2023

RV Generator Keeps Shutting Off? Troubleshoot Guide 2023

Have you ever experienced your Onan RV generator shutting off unexpectedly? This can be a frustrating and potentially dangerous problem, mainly if you rely on the generator for power while traveling or camping. Fortunately, several preventive measures can help keep your generator running smoothly.

Regular maintenance checks are crucial to prevent unexpected shutdowns. The manufacturer’s manual provides a checklist of items to check at specific intervals. Regular maintenance is essential for checking the oil level, air filter, and fuel lines. Running the generator for a few minutes monthly can also help keep it in good working order.

Extreme weather conditions, such as hot temperatures, can cause the generator to stop running. Checking the valve operation and cleaning the spark arrestor are preventive measures.

By following these preventive measures, you can avoid unexpected shutdowns and ensure that your Onan RV generator runs smoothly when needed.

Table of Contents

Possible Reasons for Onan RV Generator Shutting Off

YouTube video

Low Fuel Level

Low fuel levels are common reasons an Onan RV generator keeps shutting off. When the fuel level in the generator’s tank reaches a critically low point, it can cause the generator to shut off automatically. 

This safety feature prevents the generator from running out of fuel completely, which could damage its internal components.

If you suspect your Onan RV generator is shutting off due to low fuel levels, check the gauge on your dashboard or near the generator. 

If it’s low, refuel immediately and restart the generator. If this doesn’t solve the problem, another issue may be causing the shutdowns.

Clogged Fuel Filter

Another possible culprit behind an Onan RV generator shutting off is a clogged fuel filter. A dirty or clogged filter can prevent enough fuel from reaching the engine, causing it to stall unexpectedly. This can be especially problematic if you use your generator in dusty or dirty conditions.

To fix this issue, locate your generator’s fuel filter and remove it for inspection. If it’s dirty or clogged with debris, replace it immediately with a new one and restart your generator. Regularly inspecting and replacing your fuel filter can help prevent future shutdowns caused by this issue.

Faulty Spark Plug

A faulty spark plug can also cause an Onan RV generator to shut off unexpectedly. The spark plug provides the necessary spark for combustion within the engine. If it’s not working correctly, your engine won’t run smoothly or may not start at all.

To diagnose this issue, remove and inspect your spark plug for any signs of wear or damage. If you notice any problems with it, such as fouling or corrosion, replace it with a new one and restart your generator.

Overheating Due to Lack of Ventilation

Lack of proper ventilation around your Onan RV generator can lead to overheating issues that cause frequent shutdowns. When the generator is running, it generates a significant amount of heat that needs to dissipate to prevent overheating.

To prevent this issue, ensure that your generator has enough space around it for proper ventilation. 

Keep the area around the generator clear of debris and other objects that could block airflow. Additionally, regularly inspect and clean your generator’s cooling system to ensure it’s functioning correctly.

Low Oil Pressure or Oil Level

Finally, low oil pressure or oil levels can also cause an Onan RV generator to shut off unexpectedly. 

The engine uses oil to lubricate its internal components and reduce friction between moving parts. The engine can’t function correctly without enough oil and may shut down automatically.

Regularly check your generator’s oil level to fix this issue and add more if necessary. Also, inspect your oil filter for any signs of wear or damage and replace it if needed. 

Regularly maintaining your generator’s oil system can help prevent shutdowns caused by low oil levels or pressure.

Troubleshooting Steps: Checking Fuel and Oil Levels

Checking Fuel and Oil Levels

Regularly checking your RV generator’s fuel and oil levels ensures it runs smoothly and efficiently. Low fuel or oil levels can cause the generator to shut off unexpectedly, leaving you without power when needed. 

This section will discuss some troubleshooting steps for checking fuel and oil levels and some common issues that may arise.

Air Filter Issues

One issue that may cause your RV generator to shut off is a clogged air filter. Over time, air filters can become clogged with debris, dust, and other particles, restricting airflow to the engine. This can cause the engine to overheat and shut off unexpectedly.

Cleaning the air filter is a simple step for the RV owner. To clean the air filter, remove it from its housing and gently tap it against a hard surface to remove any loose debris. 

If there’s still dirt or debris on the filter, use compressed air or a soft-bristled brush to clean it thoroughly.

If cleaning the air filter doesn’t solve the problem, it may need to be replaced. A technician can help diagnose if the air filter is the issue or if there’s another problem causing the generator to shut off.

Fuel System Issues

Another common issue that may cause your RV generator to shut off is a problem with the fuel system. Low fuel levels, a clogged fuel line or tank vent, or a faulty fuel pump can all cause problems with your generator’s ability to run correctly.

To check for low fuel levels, locate your RV’s fuel tank and check how much gas is left in it. If there isn’t enough gas in the tank to run your generator for an extended period (at least several hours), fill up at a nearby gas station before continuing on your journey.

If you suspect an issue with your RV’s fuel system (such as a clogged fuel line or tank vent), having a technician look is best. They can diagnose the problem and recommend the necessary repairs.

Oil System Issues

Finally, low oil levels or issues with your RV’s oil system can also cause your generator to shutting off unexpectedly. To check for low oil levels, locate your RV’s oil dipstick and the engine’s oil level.

If the oil level is low, add more until it reaches the recommended level. Be sure to use the correct type of oil for your RV’s engine (check your owner’s manual for details).

If you suspect an issue with your RV’s oil system (such as a faulty oil pressure switch), having a technician look is best. They can diagnose the problem and recommend any necessary repairs.

Troubleshooting Steps: Cleaning or Replacing Air Filter

Check the Spark Plug for Signs of Wear or Damage

To troubleshoot why your Onan RV generator keeps shutting off, it’s essential to start by checking the spark plug. A worn or damaged spark plug can cause the generator to shut off unexpectedly. To inspect the spark plug:

  1. Remove it from the engine and examine its condition.
  2. Look for signs of wear, such as cracks, corrosion, or fouling.
  3. If you notice any damage, replace it with a new one.

Inspect the Ignition Key to Ensure It Is in the “On” Position

Another reason why your Onan RV generator may be shutting off is due to an incorrect ignition key position. 

The ignition key must be in the “on” position for the generator to operate correctly. Therefore, inspect the key and ensure it is turned on before starting your generator.

Test the Spark by Removing the Spark Plug and Grounding It Against the Engine Block

Testing your spark plug is necessary if you have checked both spark plugs and ignition keys without any issues. 

To determine whether there is a spark between your engine’s coil and the ground when turning over its starter motor, remove one of its plugs from its cylinder head, then connect this part back onto its wire lead while holding onto it manually (or using pliers). 

Ground this metal portion against some exposed metal surface around where you had removed another plug earlier (e.g., cylinder head fins). 

Turn over its starter motor again while observing if sparks are jumping across these two points.

Clean or Replace Carburetor if It Is Clogged or Dirty

A dirty or clogged carburetor can also cause an Onan RV generator to shut off frequently. In addition, dirt and debris can accumulate in carburetors over time, affecting their performance. To clean a carburetor:

  1. Turn off your generator’s fuel supply valve and disconnect any attached hoses.
  2. Remove all screws that hold together various parts of the carburetor, then carefully disassemble and clean each component using a carburetor cleaner.
  3. If cleaning doesn’t solve the issue, consider replacing the carburetor.

Look for Signs of Vapor Lock, Such as a Hissing Sound from the Fuel Tank

Vapor lock is another reason your Onan RV generator may shut off frequently. This condition occurs when fuel in the generator’s fuel system vaporizes due to high temperatures or low pressure. 

One sign of vapor lock is a hissing sound from the fuel tank. To fix this issue, try loosening or removing the gas cap to relieve any pressure buildup.

Test the Armature Coil and Wire Connections for Any Issues

The armature coil and wire connections are also essential components that need checking if your Onan RV generator keeps shutting off unexpectedly. 

Check whether there are any loose or damaged wires and ensure all connections are tight and secure. If you find any damage or issues with these parts, replace them immediately.

Check Piston Rings for Wear or Damage That May Prevent the Generator From Starting

Finally, check your generator’s piston rings for wear or damage that may prevent it from starting up correctly. Worn-out piston rings can cause poor compression levels in your engine, leading to frequent shutdowns. Scrutinize the rings and replace them if necessary.

Troubleshooting Steps: Inspecting Spark Plug and Ignition System

Error Codes: Understanding the Underlying Issues

When a generator shuts off unexpectedly, it can be frustrating and stressful, primarily if you rely on it for power. 

However, error codes can provide valuable information about what’s causing the problem. Familiarizing yourself with these codes and their meanings can help you diagnose the issue more accurately.

Some common issues that trigger error codes include low oil pressure, overloading, and overheating. For example, if your generator is overloaded, it may shut off and display an “overload” error code. 

Similarly, you may see corresponding error codes if there’s low oil pressure or the engine is overheating.

Inspecting Spark Plugs: A Key Step in Troubleshooting

One potential cause of generator shutdowns is a faulty spark plug or ignition system. To troubleshoot this issue, start by inspecting the spark plug. 

Then, remove it from the engine and examine its condition. If there’s heavy carbon buildup or damage to the electrode tip, it may need to be replaced.

Additionally, check the ignition key and ensure it’s in good condition and adequately inserted into the switch. 

If everything checks out with the spark plug and ignition key, but you’re still experiencing issues with your generator shutting off unexpectedly, inspect other ignition system components.

Troubleshooting Ignition System Components

Other potential culprits behind generator shutdowns include issues with the carburetor or vapor lock in fuel lines. Scrutinize these components to ensure they’re functioning correctly.

Another possible culprit could be a faulty armature coil or wire connection between your generator’s ignition system components. 

Again, check these components for signs of wear or damage that could interfere with proper function.

Watching instructional videos on how to troubleshoot specific error codes can also be a helpful resource in resolving generator output problems related to spark plugs and ignition systems.

Troubleshooting Steps: Resetting the Circuit Breaker

Regularly Perform Maintenance Checks on Your Onan RV Generator

Regular maintenance checks on your Onan RV generator are essential to ensure it runs smoothly. It’s important to follow the instructions in your generator manual for proper usage and maintenance. 

A tripped circuit breaker is one of the most common issues with an Onan RV generator, which can cause the generator to shut off unexpectedly.

Follow These Steps to Reset the Circuit Breaker

First, locate the starter or house battery switch to reset the circuit breaker and turn it off. Then, find the control board and remove its cover. 

Look for a small button labeled “Reset” or “Trip.” Press this button firmly until you hear a click. Then, replace the control board cover and turn on the starter or house battery switch.

Check the Voltage Output of Your Generator

Another issue that can cause your Onan RV generator to shut off is low voltage output. To check if this is causing your issue, use a voltmeter to measure the voltage output of your generator while it’s running. 

The recommended range for voltage output varies depending on your specific model of Onan RV generator, so be sure to consult your manual.

Keep an Eye on Fuel Level

It’s also important to keep an eye on the fuel level of your gas generator and refill it as needed. Running out of fuel can cause unexpected shutdowns and damage your generator.

Consider Professional Genset Technician Service

If you’re experiencing issues with your Onan RV generator despite performing regular maintenance checks and following these troubleshooting steps, consider servicing it by a professional genset technician. 

They will have experience working with generators like yours. In addition, they can diagnose any underlying issues that may be causing problems.

Troubleshooting Steps: Investigating Error Codes

Check the Starter Switch to Ensure it’s in the “On” Position.

One of the most common reasons for error codes on an Onan RV generator is simple – the starter switch may not be in the “On” position. 

This can happen quickly, especially if you’re new to using an RV generator. So make sure that you check this first before moving on to more complicated troubleshooting steps.

Verify That the House Battery is Fully Charged and Connected Properly

Another reason why your Onan RV generator might be displaying error codes is due to a dead or improperly connected house battery. 

Without a fully charged battery, your generator won’t be able to start up properly. So inspect your battery regularly and ensure it’s always fully charged and connected correctly.

Inspect the Control Board for Any Signs of Damage or Loose Connections

Suppose your starter switch is in the “On” position, and your house battery is fully charged. However, you’re still experiencing issues with your Onan RV generator. 

In that case, it’s time to look closely at the control board. Inspect it carefully for any signs of damage or loose connections that could be causing problems with your generator.

Try Resetting the Circuit Breaker Switch

Finally, if everything fails, try resetting the circuit breaker switch on your Onan RV generator. This can clear up any issues related to tripped breakers and get your generator running smoothly again.

Preventive Measures: Regular Maintenance Checks

Check the Fuel Level in the Generator’s Fuel Tank

Before starting your RV generator, it is essential to check the fuel level in its fuel tank. Running out of fuel while operating your generator can cause severe damage. Therefore, ensure you have enough fuel before turning on your generator.

Inspect the Fuel Pump and Fuel Line for Any Signs of Damage or Clogging

The fuel pump and fuel line are essential components of an RV generator. They work together to ensure the right amount of fuel is supplied to the engine during operation. 

In addition, regular inspection of these parts can help prevent clogs and leaks. If you notice any signs of damage or clogging, it is best to address them immediately.

Ensure That the Fuel Cap Is Tightly Secured on the Gas Tank

A loose fuel cap can cause problems with your RV generator’s operation. It can lead to air entering the system, negatively affecting its performance. Ensure you secure the fuel cap tightly after adding gasoline to avoid this issue.

Verify That the Oil Level Is Sufficient and Not Too Low

Regularly checking your RV generator’s oil level is crucial for its smooth operation. Low oil levels can cause overheating and other issues that may result in costly repairs or parts replacement. Check your owner’s manual for instructions on how often you should check your oil level.

Check the Location of the RV Fuel Tank to Ensure That It Is Not Causing Any Issues with The Generator’s Fuel Supply

The location of your RV’s fuel tank can affect how well your generator runs. For example, it is too far from where you are operating your generator. In that case, it may result in a weak flow rate or low pressure, causing operational issues with your equipment.

Test The Oil Pressure Switch To See If It Is Functioning Properly

The oil pressure switch is critical in ensuring sufficient oil pressure inside an engine during operation. A faulty switch can cause damage to the engine and lead to costly repairs. Therefore, regularly testing this switch is vital to ensure it functions correctly.

Preventive Measures: Using Quality Fuel and Oil

High-quality fuel and oil are crucial in maintaining your generator’s optimal performance and longevity. In this section, we will discuss some preventive measures that you can take to ensure a consistent fuel supply to the engine.

Use High-Quality Fuel

The quality of fuel you use can significantly impact the performance of your generator. Using low-quality fuel may cause clogging in the fuel filter, leading to insufficient fuel flow to the engine. 

This problem can result in poor performance or even damage to your unit. To prevent this, always use high-quality fuel from a reliable source.

Check the Fuel Filter Regularly

Regular fuel filter checking ensures proper fuel flow to your generator’s engine. In addition, the filter prevents debris and contaminants from entering the engine, which can cause clogging and damage. 

However, dirt and debris build up on the filter over time, reducing its efficiency and causing engine performance problems. Therefore, checking and replacing your generator’s fuel filter regularly is crucial.

Using recommended oil for your generator’s engines ensures optimal performance and longevity. 

However, different generators require different types of oil, so it is essential to check your manufacturer’s specifications before purchasing any oil for your unit. Also, change the oil regularly, as the manufacturer recommends.

Correctly Fill the Propane Tank

If your generator uses propane as a power source, ensure you fill up its tank correctly before using it. A poorly filled propane tank may cause insufficient pressure in the system leading to poor performance or even damage your unit. 

Additionally, ensure that all connections are tight and that there are no leaks in any part of the propane system.

Monitor Power Load and Pressure

Monitoring power load is critical when operating generators, as overloading may lead to potential damage or failure of a unit. 

Keep track of how much power is used at any given time while using the generator. Additionally, monitor pressure levels regularly to ensure it’s within the manufacturer’s recommended range.

Keeping Your Onan RV Generator Running Smoothly

Regular maintenance checks are crucial to keep your Onan RV generator running smoothly. Neglecting routine maintenance can lead to frequent shutdowns, costly repairs, and even permanent damage to your generator. 

Following the troubleshooting steps and preventive measures outlined in this post, you can ensure your generator stays in top condition.

One of the most common reasons for an Onan RV generator shutting off is low fuel or oil levels. Regularly checking these levels and topping them up can prevent sudden shutdowns. Another important step is cleaning or replacing the air filter periodically

A dirty air filter can restrict airflow to the engine, causing it to shut down.

Inspecting the spark plug and ignition system is also essential for the smooth operation of your generator. A worn-out spark plug or faulty ignition system can cause misfires and shutdowns. Resetting the circuit breaker may also solve some issues with your generator.

If none of these steps work, investigating error codes displayed on the control panel could help identify any underlying problems with your generator. 

But, again, taking care of these issues early on can prevent further damage to your equipment.

In addition to troubleshooting steps, regular maintenance checks are crucial for keeping your Onan RV generator running smoothly. 

Scheduling periodic oil changes, tune-ups, and overall inspections by a professional technician will help identify potential issues before they become significant problems.

Quality fuel and oil are other preventive measures that can prolong your generator’s lifespan. However, using substandard fuel or oil can create deposits in the engine that may cause clogs and reduce performance over time.


Why does my RV generator keep turning off?

Your RV generator may turn off due to low fuel levels, a dirty air filter, or overheating. Regular maintenance can help prevent these issues and ensure your generator runs smoothly.

Why does my generator randomly shut off?

Random shutdowns could be due to a variety of issues, from low oil levels and faulty carburetors to blocked fuel lines. Always consult the manufacturer’s manual for specific troubleshooting guidance.

Why does my generator run for 20 minutes then shut off?

If your generator runs for a while then shuts off, it could be overheating. Check for proper ventilation, clean the cooling system, and ensure the oil level is adequate.

What does 3 blinks mean on a Onan generator?

Three blinks on an Onan generator typically indicate a service fault. Check your Onan manual for the specific fault code interpretation, as it varies by model.


Our team at HighwayDI is a group of passionate RV owners, mechanics, and industry experts who have come together to create the ultimate resource for RV troubleshooting and maintenance. We believe that the best way to learn is through hands-on experience, and we're committed to sharing our expertise with you.