How to Start Onan RV Generator (9 Steps Guidelines)

Whether you are in the market for a new RV generator, or you want to upgrade an existing one, Onan offers excellent power and portability along with effortless start-up operation. They offer easy remote switch start-up which is an excellent thing for your RV.

However, sometimes the Onan start switch located inside your RV doesn’t work. If that’s the case with you and you don’t know what to do with your cranking Onan RV generator, we’ve got you covered. Continue reading below to find out how to start your Onan RV generator when it’s not.

How to Start a Cranking Onan RV Generator

First of all, try starting it two or three times before doing anything else. Because when left unused for a while, generators take a few attempts to start.

Step 1. Prime the Generator

A lot of people don’t know this, but there’s another functionality that your RV’s generator remote button offers. It can prime the generator too. Just hold the Off button down for a few seconds (preferably 5-10 seconds) and let go of it. This pushes down fuel into your generator, which is called priming.

Priming your generator is a must if you haven’t used it for a while. Prime it a couple of times at least. Then, press and hold the On button. Hold it for ten seconds, then prime it again. Do the whole thing for a couple of times. Your Onan RV generator should start now.

Still no luck? Move on to the next step.

Step 2. Prime it From the Outside

There’s another way to prime your generator, and that is from the outside. There’s a start button located on the generator body. So, go outside of your RV, open up the generator cover to reveal your Onan generator, and locate the On button. Then hold the Off button for about ten seconds, then push On and hold it for a couple of seconds. Repeat the entire process a few times.

Remember not to prime your generator for more than 30 seconds at a time. Over-priming will further stop your Onan generator from starting up.

Step 3. Check the Aux Battery

The next thing you should check is to check your RV’s aux battery. Because, most of the time when you let your generator sit out for long, the battery dies. Your aux battery can come in handy in that case. It can help your generator to start.

However, aux batteries, too, tend to dry up on electrons when left out for long. You can plug it in inside your house to get it charged and then try to start your Onan generator again. Generally, your aux battery needs to provide 5 to 8 volts in order to start up your RV generator.

Step 4. Level Your RV

In the case of RV generators like Onan generators, there is no level sensor. However, there’s an oil level indicator that can help you determine whether your RV is on level ground or not.

So, when you are absolutely certain that the oil level is not low, but it is still showing a little low on the indicator, your RV is not on level ground. This happens more than you think it would and it prevents your Onan generator from starting. Level your RV and it should start right up.

However, if you are in a parked situation and don’t want to move your RV, you can always refill your oil a bit and try starting your Onan RV again. Your Onan can indicate this with two flashing lights, so look out for that.

Step 5. Check for Bad Gas

In the case of RV generators like Onan, they get their gas from your RV’s fuel tank. So, if your gas level is low (about one-quarter), it will prevent your generator from starting. So, keep your gas above that level.

Also, if your RV’s been sitting out for a long, the best practice is to replace the gas with a fresh bunch because it might have gone bad, which too will prevent your Onan generator from starting up.

Step 6. Check The Cables

There are a bunch of cables on your Onan RV generators. Check them, and make sure everything is connected. Sometimes, when you are on a bumpy road for too long, your generator cables might fall out of their sockets. And while you are at it, check your circuit breakers too. 

Step 7. Check Your Air Filter

Normally, a dirty air filter won’t stop your Onan from starting. However, if it’s clogged up to the point where air can’t get in at all, it will certainly stop the generator from starting. Give the air filter a good rinse and wash. Afterward, soak it in a bit of oil before reattaching it back to its place.

Step 8. Use Starter Fluid

This method requires opening up the air filter. So, grab a can of starter fluid. Remove your air filter and spray the starter fluid in, underneath it. There’s a vent to let air in. Spray the starter fluid in a manner that the fuel goes in. Then close everything up and try to start your generator.

If this works for you, it means that you’ve got a fuel problem. So, change the fuel as soon as you can.

Step 9. Monitor and Troubleshoot

After you’ve managed to start your RV generator successfully, keep an eye on how it performs. Things you should check for are:

• proper voltage output
• stability in frequency
• warning indicators (if any)

If you notice anything out of the ordinary, stop your RV generator immediately and do a thorough inspection.

FAQs – Frequently Asked Questions and Answers

How do you turn on an RV generator?

Just like the method we’ve explained for the Onan RV generator, to turn on any RV generator, you need to use the remote start button located inside the RV. Prime it first, then turn it on by pressing the on button.

Which batteries start the generator in an RV?

The aux battery used for the interior of your RV is also used to start up your RV generator. Typically, any 12 volts lead acid battery can do the job.

How do you start a generator in a manual procedure?

To manually start a generator, turn the fuel valve on, turn it on, choke, then turn on the ignition. If this method fails, locate the recoil cord and pull it to start the generator manually.

What is the voltage of an RV?

RV generators provide power with a 30 Amp three-prong plug, which puts out 120 volts. Your RV power cord goes directly into it.

Final Words

When your Onan RV generator doesn’t work, make sure to prime the engine first, then retry. Normally, that’s all you need to get it working again. However, for RVs that’s been sitting idle for a long, make sure to do a proper inspection of oil, fuel, battery, etc., and then start the whole starting process. Also, do proper maintenance from time to time to keep your Onan RV generator always ready for your next adventure trip.