Updated: December 22, 2020

Generac 5939 GP5500 Portable Generator Review

by Charles Jasper

Product Overview

Among the many who choose to use a portable generator, the Generac 5939 GP5500 is a model that has a lot to offer for very specific groups. Those that work in heavy-duty environments or have specific tasks will be best suited for this particular generator.

In terms of power, this portable generator uses a 389cc OHV engine complete with splash lubrication. Its exterior is comprised of a steel frame that includes foldable handles and wheels that do not need to be inflated even after long-term use.

The Generac 5939 GP5500 also includes 5 covered power outlets that support both 120-volt and 240-volt power options. This portable generator also includes a starting mechanism that requires ripcord functionality rather than some of the more popular electric push button.

With its 6,875-surge wattage and consistent 5500-wattage, this portable generator is a great choice for those in need of a lot of power for shorter periods.

Generac 5939 GP5500 Portable Generator

Generac 5939 GP5500 Portable Generator
  • 5500 Running Watts
  • 6875 Starting Watts
  • 7.2 gallons fuel tank
  • Up to 10 hours of run time
  • 180 pounds weight

Benefits of Portable Generators

As generators become increasingly popular, the need for them to become more mobile and convenient has also steadily increased. While standard generators have provided users with the power to complete a seemingly endless variety of jobs, portable generators have begun to take things one step further.

Above all other benefits provided with the use of a portable generator is the element of mobility. A portable generator provides power whenever and wherever you may need it, which makes it essential in the event of major power outages associated with hurricanes or other natural events. Most portable generators achieve mobility through the use of wheels connected to the bottom of the generator, or through handles which allows for transport via carrying.

While some portable generators may be heavier than others, there are a growing number of options that provide the mobility of a portable generator with the compact design associated with smaller power source options. Many of these options also include travel bags when possible allowing even more visual appeal and convenience.

Another aspect of portable generators that seems to be of considerable significance is the ease of use associated with them. Unlike standard generators that are often larger and much more technologically complex, portable generators often have some of the most simplistic instructions.

As these devices can be purchased from standard hardware stores, there are no advanced technical skills needed to operate these machines. Generally, the operation is governed by a push-button start mechanism with the possibility of additional features such as remote controls or even cold weather start technology which makes operational start-up easier in extreme climate conditions.

The safety features often found with portable generators also have a large amount of appeal to those who may want to use these as a heating alternative. When you consider purchasing a generator, it is natural to feel a bit hesitant or concerned at first. Luckily, portable generators are perfectly safe even for the most novice of users.

Portable generators come with circuit breakers, mechanisms to regulate voltage, and, in some cases, inverter technology. This allows for the production of clean energy which not only enables you to power smaller electronics but also benefits the overall environment and ecosystem.

Whether you are choosing to use your portable generator for possible emergencies or require it for daily tasks, a good quality generator could be a lifesaver. The benefits associated with the use of portable generators far exceeds any of the virtually nonexistent risks or concerns you may have. The versatility found In some of the more popular models such as the Generac GP5500, make them an absolute necessity.


While many portable generator models include electric push-button or remote start mechanisms, the Generac 5939 GP5500 does not. This portable generator does lend itself to more convention uses and omits new technology features that could prove to be attractive to some users.

Instead of an electric push-button option, this portable generator uses a pull-cord mechanism. The pull-cord, while not particularly appealing at first, has been proven to be quite successful for most users. In many cases, the pull-cord catches within the first one to two attempts and the engine starts fairly easily even in colder temperatures.

Though this has been consistently reported, those in more extreme climates may want to be a bit more cautious as the possibility of freezing temperatures could affect the ease of use upon attempting to start the generator


As with many aspects of the Generac 5939 GP5500, there were not a significant number of robust features added to the outlets and connections for this portable generator. While this is the case, however, the outlets provided are more than adequate for the average user both at home and out on the road.

This portable generator includes a plethora of outlets designed for both 120- and 240-volt usage. In total, there are five three-pronged outlets. Four of these outlets operate at 120 volts while the fifth outlet can be toggled back and forth between 120 and 240 volts. This convenient feature adds a great deal of versatility to the generator and makes it suitable for multiple tools and heavy-duty appliances you may be using.

The only slight drawback to the connections on the Generac 5939 GP5500 is the absence of a dedicated 12-volt DC outlet, as well as an RV-ready twist-lock outlet. Though not used by everyone, these features make it less than ideal for contractors who often find the 12-volt DC outlet handy, and RV travelers who rely heavily on the twist-lock outlet. If you don’t fall into one of these two categories, however, this Generac portable generator should be capable of sustaining most of your needs overall.


With portable generators functioning as an additional power source in most cases, the possibility of noise is of great concern. Portable engines contain motorized parts which, in turn, can cause a certain level of noise. Though this may not cause a problem for all users depending on your intended use, the noise associated with a portable generator could prove to be an issue if you happen to be using a campsite or are close to others.

The composition of the engine usually plays a significant role in the amount of noise generated by portable generators. The Generac 5939 GP5500 has an encased motor using a hardened steel structure. While this makes for great durability, it does contribute to the noise level produced by the generator.

Generac has tried to counter this effect however, with the use of a low-tone muffler. This specialized muffler is designed to lessen the noise produced during operation. It also comes with a motor supported by motor mounts at various points to minimize vibrations and keep operation smooth and consistent.

In most cases, these features have lessened some of the noise associated with the generator, however, it may not be sufficient for some as its run at approximately 70 dB. This is much louder than a standard conversation and could be considered similar to the sound of a hairdryer which may drown out conversations.

Power & Performance

In terms of power and performance, the Generac GP5500 has a great deal to offer its users. Compared to other generators of similar size and build, it excels with a substantial 6875 watts of surge power. This adds a great deal of value if you happen to be running a construction site with multiple power tools or find yourself in an emergency. In terms of running power, this portable generator gets 5500-watts which is amazingly good. Power of this magnitude can generally satisfy the majority of needs and goals.

The engine included in the Generac 5939 GP5500 operates at 389cc and has been built with longevity in mind. Complete with splash lubricant, this engine has been manufactured with the goal of a long-lasting product. There have been some reports of issues with the engine components and leaks in between the carburetor and engine. These issues could certainly be cause for some concern as they can often be costly to repair.

Though this is the case, the chances of this specific type of issue are fairly minimal based on several owner testimonials and reports. If you find yourself with an issue, the 2 – year manufacturer warranty should be more than sufficient to address the concerns adequately


Considering the straightforward approach taken by Generac in designing this generator, it should come as no surprise that it runs on standard gasoline rather than propane. Currently, there is no known way to convert this portable generator to a duel-gas model so users will need to be comfortable and satisfied with traditional gasoline.

Though the Generac 5939 GP5500 does not include the more sophisticated use of propane, its traditional stance does make for a more affordable gas option. The 7.2-gallon tank included with the generator has a maximum runtime of 10 hours when used at half-load. This is considerably less than many other portable generator options available on the market, especially for the size and power. This lesser runtime makes it an ideal purchase for those who may have a very specific job or only need to power a handful of smaller tools.

Another drawback to the Generac portable generator is the lack of a fuel gauge or low-oil indicator. With the lack of either of these functions, this portable generator allows its competitors to surpass it in terms of efficiency. When the tank has run out of oil, it will shut-off without any true indication as to the reason for the stoppage. While many experienced generator users may not mind this particular functionality, it may not bode well for the more novice user who may be unaware of the reasons behind the shutdown.


While the Generac 5939 GP5500 has a few less than ideal qualities in other areas, its portability is quite ideal. The 180-pound portable generator is designed specifically for travel. The steel frame includes a fold-down handle made from rubber that locks allowing it to be towed across various terrains.

Additionally, the portable generator includes wheels that are made of rubber but do not need to be inflated. This makes for a considerably durable device with very little in the way of maintenance.

The exterior of the Generac 5939 GP5500 also enhances its portability. Made of steel, it is ideal for those who may choose to work construction-based jobs or those that may be working in tougher conditions.


  • CARB Certified – The state of California has a very specific and stringent group of regulations related to emissions and their effects on the ecosystem. The Generac 5939 GP5500 is currently certified under these regulations making it accessible to users in all 50 states
  • Includes low-oil shutdown – Though it does not include a low-oil sensor, this portable generator does include a low-oil shutdown feature that helps to avoid any potential damage from low oil contents
  • Heavy Duty and Durable – The Generac 5939 GP5500 has a metal exterior that makes it ideal for construction sites or environments that may have rough terrain.


  • Weight may be a bit too heavy for some users – The Generac 5939 GP5500 weighs 180-pounds. While it does come with handles and wheels for additional portability, trying to transport this generator may be difficult for one person alone.
  • Noise may be too much for some users – At 70 dB, the noise associated with the Generac 5939 GP5500 will easily overpower most standard conversation levels. Those who are using their generator for emergency purposes or camping may be better suited for quieter generator options


While there are certainly a few less than appealing aspects associated with the Generac 5939 GP5500, it still proves to be a reliable and solid choice for those in need of a medium-sized portable generator. Its power and durability make this a great choice for those who need a sturdy portable generator which could be exposed to less than ideal conditions. Most of the potential drawbacks can be easily overcome and ultimately, this generator is worth consideration depending on the type of results you need.

About the author

Charles Jasper is the owner and main author of Generator Guider. He has a degree Engineering and 20 years experience on using generators on various projects, around the house, and while traveling and camping. He has a passion for everything related to home improvemen and loves to travel on his RV. When he is not working, you might find Jasper working on projects around the house or organizing a camping trip.