Onan Generator Starts Then Shuts Down – How To Fix It?

Generators have become must-have equipment since they are a significant power source during power outages. These machines are also useful while camping, fishing, leisure trips, etc. For example, a good generator for bowfishing makes your fishing experience convenient and enjoyable.

Onan is a well-known brand when it comes to generators for recreational trucks. They build good quality generators that produce a lot of power while running in low noise; this makes them ideal for camping trips. Nonetheless, there have been incidences where users have complained about operational failure. Some have reported Onan generator starts then shuts down.

This article focuses on how to fix this problem. It’s a normal thing that shouldn’t worry you. You can easily fix it yourself if you identify the cause. Here, we’ll list some possible causes and suggest the best method to fix them. Stay with us.

Why Is My Onan Generator Starts Then Shuts Down?

There is no specific answer to this question. Your Onan generator may start then shut down for various reasons; this can be annoying and inconvenient. Sometimes this happens when your generator has been sitting idle for a long time. Most importantly is to identify the particular cause and deal with it.

Why Is My Onan Generator Starts Then Shuts Down

Below are some of the most common reasons why your Onan generator would start then shut down and how to solve them:

1. Low Fuel

Undoubtedly, your generator won’t run without fuel. Low fuel in the gas tank will certainly cause your generator to start then shut down after some time. It may have enough fuel to start; however, it shuts down when loaded. Solution: Check your fuel gauge to ensure you have enough fuel; if not, refill.

2. Low Oil Level

Low oil levels may cause your Onan generator to start then shut down. While most generator users tend to think that a generator will not start due to low oil levels, it will start but could likely cause damage. Newer generator models have oil sensors and pressure switches that automatically shut down the generator if the oil level is low. Solution: Refill your oil if it’s below the recommended level.

3. Overloading

Most newer generator models have a built-in safety mechanism that shuts down the engine when overloaded. It helps protect the control board components against high voltage. Each generator has a maximum power limit that it can handle; your generator will automatically shut down if the power limit is exceeded. Solution: unplug all appliances before starting your generator. Check the power rating of your appliances before plugging them into the generator.

4. Engine Problem

Engine faults can occur depending on the handling and usage of your generator and could be responsible for your generator starting and shutting down. Such problems can be challenging to diagnose. Solution: Consult a professional or expert dealer.

5. Battery Problem

The battery is essential for starting your generator; it produces the necessary power to turn on the engine. If the battery is not properly charged or dead, your generator may fail to start or run for a few seconds then shut down. Solution: Ensure your battery is sufficiently charged. If you have a dead battery, consider replacing it.

6. Choke Position

A choke is an oxygen regulator switch; it regulates the amount of oxygen that gets into the carburetor, hence increasing the flow of fuel. The choke should be at full choke (closed) for your generator to start. Leaving it closed cuts off air, causing a fuel-to-air imbalance and your generator shuts down. Solution: Start your generator when the choke is closed, then steadily push it to open as the generator runs.

7. Sensor Failure

Modern generators have several sensors for different functions. Such sensors include coolant temperature sensor, oil pressure sensor, exhaust gas temperature sensor, fuel pump sensor, return oil temperature sensor, etc. These sensors often fail and cause your generator to start then shut down. Solution: Identify the faulty sensor and replace it. You may be required to reprogram your generator after replacing a sensor.

8. Clogged Air Filter

An air filter is meant to clean the air that enters the carburetor. Depending on the environment where you use or store your generator, the air filter can get clogged with dust particles and debris. A clogged filter limits the right amount of air needed in the carburetor for your generator to run smoothly. This will cause your generator to shut down after a few minutes of operation. Solution: Remove the air filter and clean it; replace if need be.

9. Bad Spark Plug

The spark plug is responsible for igniting the spark that starts your generator. Sometimes dust, debris and soot may build up around the spark plug, preventing it from functioning as intended. A loose connection can also cause the spark plug to malfunction. A dirty or bad spark plug may cause your generator to shut Solution: Unplug the spark plug and clean it properly. Check for loose connection. In some cases, replacing the plug is necessary.

10. Faulty Exhaust System

If there is a problem with your generator’s exhaust, for example, a blockage or damage, it may not run for more than a minute. It shuts down seconds after starting because it cannot release the exhaust. Solution: Ensure the exhaust is not damaged or blocked. If it’s damaged, replace it.

How To Fix Onan Generator That Starts And Shuts Down

Even though Onan generators are superbly designed and built with quality, they can develop problems over time. Most importantly, knowing how to fix some of these problems saves you money and the inconvenience of being without power.

How To Fix Onan Generator That Starts And Shuts Down

With Onan generators, there are manufacturer’s codes that indicate specific faults on your generator. It’s good to know these codes and what they mean. Below are a few error codes, what they mean and how to fix them:

Error Code Meaning How to Fix
Code 2 Low Oil Pressure Pull off the oil cap to check the oil gauge. Refill your oil
Code 4 Over Crank Reset the control board
Code 14 Over Frequency Clean or replace the carburetor
Code 15 Under Frequency Turn off your generator. Let it sit for about 2 minutes, then restart.
Code 19 Governor Actuator Overload Check for loose connections and tighten.
Code 29 High Battery Voltage Check your battery connection.

Unplug and reconnect.

Code 36 Engine Stopped Check spark plug connections or replace the spark plug.
Code 47 Ignition Check/replace your ignition switch
Code 81 Exhaust Gas Temperature Sensor Open Close the gas temperature sensor.

Here are some of the things you need to check and fix when your Onan generator starts and shuts down:

  1. Check The Oil Level – Ensure the oil is at the manufacturer’s recommended level.
  2. Check The Fuel Level – Before starting your generator, make sure it has enough gas to run the engine.
  3. Check Filters and Plugs – If your filters and plugs are dirty, clean them properly or replace them if necessary.
  4. Check Electrical Faults – Electrical faults can be difficult to fix by yourself. You can consult an authorized dealer for further assistance.
  5. Check The Sensors – Ensure all sensors are working properly and none is returning an error code.

After you’ve identified and solved your generator problem, you need to reset your generator to clear the error code. Here is how to reset your Onan generator:

  • Step 1: Locate the reset button. It’s usually the start/stop button of your generator.
  • Step 2: Hold it down for approximately 30 seconds, then release.
  • Step 3: Start and run your generator for about 15 minutes. You should be able to see if the error code has cleared.

What Is The Life Expectancy Of An Onan Generator?

Generally, Onan generators are durable and can last long if properly used. The secret behind the life expectancy of any generator is regular service and maintenance and proper storage. An Onan RV generator has a life expectancy of between 15000 and 20000 operation hours. Some go to a maximum of 50000 hours.

Final Words

Like other machines, generators have several components that can fail and cause the entire generator to malfunction. Onan generators are no different. As a generator owner, you should be capable of troubleshooting basic generator faults that might cause it not to start or trip. Remember, proper storage, regular service and maintenance can help keep your generator from developing such problems.

We hope you found this article informative and you’ll be able to solve the “start and shut down” problem easily. However, if you experience a persistent problem, do not hesitate to seek help from an authorized dealer. Always adhere to the basic safety regulations of using a generator.

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