When your old RV Onan quits—maybe right in the middle of your trip—this direct replacement brings back quiet, reliable power for your RV AC, fridge, and more, so you can keep exploring with all the comforts of home, no hookups required.
If your old generator finally gave out, this Onan QG 4000i fits in the same spot as your original. You'll still need to hook up the fuel line, electrical, and exhaust, but the major work is already done for you. Enjoy the comforts you count on—morning coffee, fully charged devices, and lights on at any hour. Plus, it has enough power to run one 13,500 BTU high-efficiency air conditioner, so you can beat the summer heat and stay comfortable wherever you park.
After a long drive or when the weather turns wet and rainy, nobody wants to wrestle with a bulky generator. With one-touch start, automatic choke, and remote switching capability, powering up is always simple, rain or shine. All you have to do is press the power button and relax. And the built-in shutoffs handle low oil, overloads, and engine quirks automatically, so you can settle in for the night with your fridge cold, your CPAP on, and no worries about unexpected shutdowns.
The built-in inverter delivers clean, stable electricity—perfect for laptops, tablets, and other sensitive electronics. No more worries about power surges or fried circuits. Your devices stay safe, your lights don't flicker, and you get reliable AC power for today's gear.
This generator uses sound-dampening technology and a special muffler to help keep things peaceful. You won't have to raise your voice for campfire stories, cut conversations short, or lose sleep to engine noise. It also meets National Park Service noise guidelines, so you can experience brilliant fall foliage in the Great Smoky Mountains or visit the steaming geysers at Yellowstone without worry.
From routine oil changes to swapping out the air filter, service is straightforward. No need to be a mechanic—just basic tools and a few minutes are all it takes to keep things running strong for years to come. And with built-in self-diagnostic capability, troubleshooting issues is faster and easier so you can spend less time on maintenance.
California residents: click here
Videos are provided as a guide only. Refer to manufacturer installation instructions and specs for complete information.
Hi everyone. Steve here with etrailer.com. Today we're looking at our Cummins Onan QG 4000i onboard RV generator. Folks, it's got 4,000 watts of power, and it's gonna run on gasoline. So, if you have an old generator that finally gave out after many, many years of great use, this Onan GQ 4000 could fit into the same spot as your original. You still need to hook up the fuel line, the electrical and the exhaust, but most of the major work should already be done for you.
And maybe you already got an RV or a camper that maybe had a spot already for one, but it just didn't come with one due to, you know, supply chain issues or those kind of things. You can get one of these and get it installed. Now you can install it yourself if you want, or you can choose to use a local dealer, and we can assist you with that on our homepage, etrailer.com. We have a dealer locator tool that'll help you pick out one close to you. If you have any questions about how to find that or anything else about this unit, please comment below and we'll get back to you.
Now, this is gonna give you instant power on demand. It's a reliable one-touch startup, so it's gonna run your AC, your fridge, and all your essentials. And it really is a super quiet operation. It has soundproofing underneath the case here, an enclosed muffler. That's gonna give you quieter days, quieter nights.
It meets all of the national park search requirements of a max 60 decibels at 50 feet. And let's go ahead and take off the top so you can kind of see the inside and see that better. So it's very simple to open and close. If you notice, none of these are locking on this unit or any of the other generator, the Cummins Onans, and that's because you're gonna have it in a compartment that that compartment itself would lock, so you won't have to worry about that. And from here, you could access your main start and stop, and then your main breaker here, as well as your oil and those kind of things for maintenance.
So I did go ahead and take off the cover screws here, so I'm gonna go ahead and take this off and move it out of the way. That's just gonna give us a little better look at the inside of the unit. Again, you got your main oil here, you've got all your switches and everything over here. Here's that quieter muffler I was telling you about, along with all the wires here coming out the side for wiring it up and everything as well. And then from the top down, you can see a little better as far as the whole unit and everything here. It has a nice universal mounting tray. It gives you that aluminum crank case and everything, as well as the enclosed muffler, again, keeping everything quiet, and everything here has suspension and everything to keep it quiet as well. So it uses the vibration isolation system that they use to do that. So again, a great, great unit, built for the long haul. You're gonna get reliable, long-lasting power. It's gonna be perfect, again, for replacing your well used original generator as well. And if you're worried about stuff, don't. You have worry-free protection because it has built-in shutoffs. If you have low oil, overloading, or any engine issues, this will automatically shut down, save in itself, so you can relax with that ease of mind as far as that goes. And as far as routine maintenance, all you have to do is some oil change, and swapping out maybe filters and whatnot. It's very straightforward. You don't have to be a mechanic. You can do it yourself with some simple tools. Folks, that is gonna wrap it up for our quick look together. I'm Steven. Thanks for watching.
Review on Onan QG 4000i Inverter Generator
Hey, Steve here from etrailer. If your old generator gave out or your motorhome’s generator bay came empty from the dealer, this Onan QG 4000i is probably the one it was meant to have.
This unit gives you 4000 watts of power, runs on gasoline, and uses inverter technology. That means you get clean, consistent power for your air conditioner, microwave, fridge, outlets, and even sensitive electronics.
It’s also super quiet. Built with soundproofing, an enclosed muffler, and a vibration system to keep it smooth. It meets the 60 decibel limit at 50 feet, so it’s good to go in national parks and campgrounds.
If your RV is generator prepped, install is pretty simple. Just connect the fuel, wiring, and exhaust. One button start from inside the RV and you’re ready to roll. It’s great for boondocking or dry camping or just running the A/C on hot days.
Maintenance is easy too. Pop open the access panel without tools and you can check your oil and wiring in a few minutes.
Bottom line, this is a quiet, reliable, inverter generator built for RV life. I recommend it all the time.
Kate F- Product Enthusiast at etrailer.com
I’ve helped quite a few customers lately who work remotely and need to charge laptops, monitors, and camera gear while they’re traveling. Whether they’re full-timing or just working from the road, one thing they all have in common is needing clean, stable power and that’s where an inverter generator makes all the difference.
The Onan inverter models, like the ones under part numbers CM25ZR, CM42ZR, or CM52ZR, are built to produce pure sine wave power, which is just a fancy way of saying they give you the same safe, consistent electricity you’d get at home. That means your laptop charger isn’t going to buzz or overheat, and you’re not putting wear and tear on your devices every time you plug in.
I always tell people, if you’re relying on your tech for work, Zoom calls, editing, charging your batteries, this is one area where you don’t want to compromise. Plus, inverter generators are quieter and more fuel-efficient, so you’re not stuck listening to a loud rumble all day while you’re trying to focus or take a call.
If your RV is your mobile office (even part-time), having an inverter generator isn’t just a luxury, it’s a smart move that protects your gear and makes work on the road way less stressful.
Sam C- Product Expert (Solar & Electrical Systems)
If you're running lithium batteries in your RV, whether you're full-time, off-grid, or just solar-prepped—an Onan inverter generator like the CM25ZR, CM42ZR, or CM52ZR is an excellent choice for reliable backup power.
These models produce pure sine wave AC output, which is essential for charging lithium batteries safely, especially if you’re using a smart battery management system (BMS). Unlike traditional generators that can deliver "rough" or fluctuating power, inverter generators deliver the clean, stable voltage that lithium chargers and inverters require. This reduces the risk of fault codes, overheating, or improper charging.
Another benefit is how well these generators integrate with modern inverter/charger systems. A lot of lithium setups use gear that expects high-quality power if you feed it unstable current, the system might reject it or shut down charging altogether. The CM42ZR and other inverter models solve that problem by producing grid-like power that your system can accept with no issue.
Because the engine speed ramps up or down based on demand, you also get better fuel efficiency which is perfect when you’re just topping off your batteries after a few cloudy days or running overnight loads like a fridge and CPAP. Many lithium users also install auto-generator start (AGS), and these models pair well with that kind of automation.
If your rig is lithium-equipped and you want a generator that won’t fight your charging setup or worse, damage it these Onan inverter models are designed with that compatibility in mind.
Do you have a question about this Generator?
Info for this part was:
At etrailer.com we provide the best information available about the products we sell. We take the quality of our information seriously so that you can get the right part the first time. Let us know if anything is missing or if you have any questions.
Thank you! Your comment has been submitted successfully. You should be able to view your question/comment here within a few days.
Error submitting comment. Please try again momentarily.