When there is no electricity, generators are a significant source of power. These devices can be useful even while you’re on a trip or camping.
Onan is a well-known manufacturer of generators for recreational vehicles. These generators are of exceptional quality and generate a lot of power while remaining quiet in operation. This makes it simple for users to feel comfy while on their camping trip.
The Onan model is far from flawless; there have been many complaints regarding operational difficulties. Among the reported issues, the “Onan generator starts then shuts down” is common. In addition, attempting to repair the machine without the right tools and skills may cause damage.
Fortunately, troubleshooting your Onan generator is not a tough operation, and if you understand the essentials, everything will be OK. (Learn How to Read Onan Generator Fault Codes)
By the end of this guide, you can learn why your Onan generator starts but wont stay running.
Why Does My Onan Generator Keep Shutting Off?
There are a lot of things that mean your generator runs for a few minutes then stops. Here are the most basic checks to do on your generator to eliminate basic problems and causes of your issues.
- Check the oil level on your generator. When you have low oil pressure under a certain threshold, the generator will shut off. As oil heats, it thins out just enough and can drop below the required oil pressure level and cause your generator to shut down. It could be a good time to change your oil and replace the oil filter in your generator.
- Check your generator’s fuel filter and see if anything is restricting the fuel supply in the fuel system to the generator.
- Check the fuel line from your fuel pump along the line for leaks. If you don’t have enough fuel in your RV tank (over 1/4 tank of fuel), the generator shuts down automatically to prevent it from using all the fuel in your RV tank.
- Check and replace your generator’s air filter.
- If it’s been a while since you changed your generator spark plugs, it’s a good idea to do so.
If these measures don’t help resolve your problem, it’s time to take a further look at why your generator runs for a few seconds then stops, or you need it inspected by a Certified RV Technician.
You could find the problem is electrical on the circuit board, control boards, or yet a more common issue is the generator dies with a problem with your fuel cap causing a fuel problem.
Why Does My Generator Shut Off After a Few Minutes?
When your Onan generator shuts down without warning, it can affect your camping or RV life dramatically.
Issues can be simple or complicated. Some issues come from the same thing, yet others are not related. Here are among the more common problems that can catch you unaware as there are no warning sounds. (Learn How to Ground a Generator When Camping)
Here are a few things you can check that are more in-depth and build on the same problem above and more to help fix your Onan generator.
Spark plugs are critical components for the running of generators. If spark plugs are defective, your generator can make a crackling or misfiring sound as the spark isn’t generated evenly.
In addition, once the chambers flood with fuel and there is no ignition, it can cause your generator to shut off. The same can happen with dirty spark plugs, so in some cases, they need cleaning while it’s recommended to change them.
A loose wire on your spark plug wiring can have the same effect on sparking, and it won’t ignite the gas as there is no electrical power getting through.
Most generators are now designed to shut down when they are overloaded. The feature is in place to protect all the components on the control board and make sure the correct voltage doesn’t pass through the system.
A simple solution to prevent a costly electrical issue is to lessen the generator’s load and restart it. For example, if you find your control board does not field flash the generator at startup, you’ll find you are not getting the correct voltage.
This is because the generator can’t generate a magnetic field that delivers an AC output.
Fuel Shutoff Valve and Level
The fuel shutoff valve lets you control the flow of fuel to your generator’s engine. It can simply be you have forgotten to open this after you have closed it when your generator hasn’t been in use. It is social knowledge your generator will run for a few minutes before shutting down once the fuel line empties. Check the fuel valve before starting your generator. (Learn How To Make A Generator Quiet For Camping)
Even when your valve is open, your Onan can stop after a few minutes if you have a low fuel level. Check your fuel tank and make sure there is enough in the gas tank, or you could drag dirt into the fuel pump and fuel filter.
A choke is a regulator for the oxygen from entering your carburetor, thus increasing fuel flow. You can find this regulator is required when starting a generator as the fuel level in the carburetor will be low. Also, this regulator is often required for colder conditions.
The choke must be at full choke to start your generator yet leaving it in this position can choke your carb with fuel, and the spark plugs can’t burn the fuel fast enough. The imbalance of air and fuel in your carb unit causes your generator motor trouble and it will shut down.
Oil levels may lead to a generator shut-off. Many think your generator won’t start when the oil level is too low. Your generator can start but could cause further damage. Newer generator models come with an oil pressure switch and automatically shut down your generator if oil levels are low.
If an engine does not receive enough air, it will shut down automatically. The air filter cleans the air before it enters your carb. If you have a dirty air filter, it stops the correct amount of air passing. Unfortunately, many air filters can’t be cleaned properly, so it is best to replace these regularly to keep your generator running fine on your road trip.
Why Will My Generator Not Stay Running?
One of the most troublesome areas can be your carburetor is clogged, or there is bad fuel in the float bowl. Bad fuel can be fixed with a good clean with carb cleaner although if the jets are clogged, you may need a technician.
If it is too bad, you may need replacement parts. To do this, follow the guides here.
Locate the model number for the part specific to your product, or you can purchase a carburetor repair kit for your Onan generator. Before replacing anything and making sure you have fixed your dirty carb issue, check the two areas that could cause an issue.
Fuel Cap Blockage
As your generator runs, it uses fuel. As this happens, air will seep into your gas tank. A fuel cap has a pinhole in it to let this air in. If the fuel cap vent gets blocked, no air can enter, and the effect is to stop the flow of fuel to the engine. To check your unit fuel cap, loosen this and see if your generator runs or still stops after a while.
The armature coil can get old and fail. With this, you’ll find you get no spark or enough spark. If your armature coil is causing problems, it may need time to cool. Once cool, start your generator and check if that fixes the problem. If you see the issues arise again, get the faulty armature coil, and replace it with a new one. (Learn How Does An RV Refrigerator Work)
How Do I Reset My Onan Generator?
If you see error codes, you will need to reset your Onan generator. Here are the steps you need to reset your generator. For example, if you see Onan Code 36, you will need to carry out any of the above fixes before trying again.
- Locate the primer button on your generator. It is on the side of the unit, under the gas tank. It also acts as your start and stop button for your generator.
- Hold the prime button for a minimum of 30 seconds.
- Release the switch and push the start button to start your generator.
- Let your generator run for 15 minutes, and make sure the fault code has cleared. If the fault code remains, it means you may require further repair on your generator, so you’ll have to contact your Onan service dealer.