Onan 4000-Watt Generator - Overview

A generator is an essential tool that every home requires. It serves power in case of emergencies. There are a number of generator brands across the world. Choosing the right one can be a challenging task. So, we've decided to review one of the most popular generators on the market, namely Onan 4000 Generator. Cummins is the world's largest generator manufacturing company. They are great at design, production, and selling diesel-powered engines. They also produce the compressed natural gas engine. Cummins has been on the market for over a hundred years. Cummins was founded in the year of 1919 by Clessie Lyle Cummins J Irwin Miller. The diesel generators are authorized by the Cummins company, certified and approved by the EPA, and have a CARB complaint. On this page, we will review one of the most popular models by Cummins, namely the Onan 4000 Watt Generator. This can be an excellent option for both residential and commercial purposes. With this, you can operate more electrical appliances at once.

Cummins Generators – Brief

Before knowing about Onan 4000 generators, let's have a close look at the highlights of Cummins to know more about Cummins generators. Cummins is a superior quality generator and is available at an affordable price.

They are famous for diesel-powered generators, which can be used as home backup or job sites to run major electrical devices. Since it is EPA approved, it is eco-friendly and doesn't make much noise. They are relatively quiet generators. All the generators from Cummins are produced using a powerful and more reliable engine, ensuring the quality and durability of the generators.

The incorporated efficient engine aids in conserving fuel and makes it energy-efficient and fuel-efficient. When it comes to the power output, they come with high power watts to deliver reliable performance. The company Cummins offers a warranty of three years. The Cummins generators are big in size but lightweight when compared to other standby generators.

Cummins generated are coated with green as a color pattern, so they are easy to identify even from a distance. In this case, the Cummins Onan 4000-watt generator is no exception. With many safety features, they help maintain their long-lasting effect.

Onan 4000 Generator – Product Review

The Cummins Onan 4000 generator meets EPA and CARB tier III standards and specifications that require. Hence, it is approved to use over 50 states, including California. With its 4000 powers, this can run 13500 BTU air conditioners along with major tools. The Onan Generator 4000 is perfectly suitable for medium-duty commercial use.

The Genset features frequency regulation, a digital voltage regulator, and a single-pole 30-Amp Circuit Breaker. There is 120-inch-long generator output to connect the main breaker panel and a remote start connector. It is compact with its decent dimension of 30 x 19.7 x 14.4 inches and lightweight at just 178 pounds.

Since the unit meets all necessary standards and specifications, making it one of the best options for commercial use. When it comes to the noise level, it operates at 60 dB at 50 feet. You can expect a sound of more than 68 dB at 10 feet. However, a typical and perfect installation usually lowers the noise level. It helps to reduce the vibration while running, thus making the process quieter and smoother. Moreover, it is a spark-arresting muffler enclosed generator, so obviously, its noise level is super quiet.

There is a microprocessor control for overload and over-crank protection. It also aids in preventing mechanical faults, loss of AC signal, and starter faults. The unit provides excellent operation and performance, and it never requires decarbonizing.

There are some other protective features, including automatic choke, replaceable air cleaner, fuel filter, and electric fuel pump with automatic shut off. It comes with a limited warranty of three years and includes 90 days adjustment policy, which covers all parts and labor service for the first two years. However, they charge for regular maintenance. It offers one year warranty for commercial use, ensuring that it is suitable for medium-duty commercial applications. The Onan 4000 generator comes with a user manual, and you can refer to it if you have any doubts about operating the generator.

Highlights of Onan 4000 Generator 

  • The Onan generator 4000 watts can be ideal for light and medium-duty applications.
  • The enclosed muffler ensures a quiet operation, so it is a relatively quiet generator.
  • Its microprocessor control with diagnostic features for protecting the unit from unnecessary damages
  • It comes with sealed connectors.
  • It is compact design and lightweight with its just 178 pounds
  • The engine is more powerful and reliable
  • They offer three years for residential and one year for commercial purposes.
  • It is EPA approved and CARB III compliant.
  • The unit meets all mandatory standards and requirements
  • The 4-point vibration isolation ensures the smooth and quiet operation
  • It is powered by a reliable Cummins-Onan OHV engine for great efficiency

Similar 4000 watts Generator 

Champion 4000-Watt Digital Hybrid

The Champion 4000 watts series is one of the best alternatives to the Onan 4000 generator. However, the Champion 4000 portable generator is quite different from Onan 400o watts. The Champion has two impressive aspects that the Onan 4000 generator doesn't include. The Champion 4000-watt series is portable and can run on either gasoline or liquid propane. Bu the drawback is it is not the best option for commercial use like Onan. There are no brands that beat the Onan generator for this option.

However, it still manages to run major job sites appliances with its high-power output. Moreover, it is more affordable than its competitors or conventional generators. Another best thing about the unit is its open-frame design. It makes portability easier.

The Champion 4000-watt generator is slightly larger than inverters but lighter than other traditional generators, thanks to its open-frame design. All generators from Champion are coated with yellow and black for easy identification. The Champion 4000 portable generator is no exception. The Champion calls this model a Digital Hybrid for its dual-fuel engine. This can be operated by using gasoline or liquid propane either.

This is relatively quiet with its incorporated inverter technology. It is compact and lightweight with a weight of 83 Ibs. The Champion 4000 watt is powered by 224cc 4 stroke OHV engine, which is powerful and reliable and helps conserve the fuel, making it fuel-efficient. With its 2.9-gallon capacity, it can run for up to 17 hours without a break.

The Champion 4000 portable generator has parallel compatibility, letting you connect another model to it in emergencies. In general, the unit generates 4000 watts as starting power and 3500 watts as running power, which means you can double the power as 8000 by connecting two-unit together. Moreover, it comes with an economy mode to adjust the engine speed based on the load, thereby ensuring engine safety and extend the engine life. Plus, it helps for less fuel consumption, thus making the unit fuel-efficient. Quiet technology, on the other hand, guarantees a quieter operation.

Overall, the Champion 4000-watt generator can be a perfect option for residential use, tailgating, RVs, and more. With its 64 dB noise level, it won't disturb your family members or neighborhoods. It sounds level is similar to the conversation of the few people. It is one of the best models by Champion due to its enhanced features and technologies.

Features Value
Starting power 4000 watts
Running power 3500 watts
Noise level 63 dBA
Run time Up to 17 hours at 25% load
Fuel gasoline
Fuel tank capacity 2.9 gallon
Engine 224cc 4 stroke OHV engine
Weight 82 Ibs

What we like in the Champion 4000 portable generator

  • It generates clean and stable power, thanks to its less than 3% THD (Total Harmonic Distortion)
  • With its 82 Ibs weight and open frame design., it is lightweight and portable
  • The powerful 224cc 4 stroke air cooled OHV engine guarantees the durability
  • It is a digital hybrid portable generator
  • This can run for up to 17 hours with its 2.9-gallon fuel capacity
  • It noises 63 dBA at 50% load, and you can reduce the noise level by adjusting the load
  • It is more affordable than its competitors
  • The unit has parallel connectivity for increasing the power.

Bestseller (lists)

Champion Power Equipment 100302 4000-Watt RV Ready Open Frame Inverter, Yellow Garden & Outdoor

  • Advanced Open Frame Inverter Design: 50% quieter and 20% lighter than a traditional Champion 3500-watt generator, plus our Economy Mode feature saves fuel and extends engine life
  • Quiet Technology and Extended Run Time: 64 dBA is great for RVs, tailgating, your next project or home backup, with 4000 starting watts and 3500 running watts for up to 17 hours run time on gasoline
  • Clean electricity for sensitive electronics: RV Ready with a 120V 30A RV, plus two 120V 20A household... Read More


If you are looking for a reliable power source for your RVs during emergencies, the Onan 4000-watt generator is a perfect choice for you. This is cost-effective and has a reliable engine of 224cc 4 stroke air-cooled OHV, which generates clean and stable power. The unit is EPA and CARB approved, so you don't have to worry and can use them anywhere. We hope that our article has helped you know more about the Onan 4000-watt generator, make use of it, and place your order on eCommerce sites like Amazon for the best deals.

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