Firman T04073 - 4000/5000W Tri Fuel Generator With Electric Start

The Firman T04073 is a portable open frame tri-fuel generator with a rated wattage of 4,000 W and a starting wattage of 5,000 W. (Read full specs)

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Price History
Price history for the Firman T04073
Latest updates:
  • $829.00 - May 24, 2024
  • $799.00 - May 23, 2024
  • $829.00 - April 28, 2024
  • $787.55 - April 25, 2024
  • $829.00 - April 22, 2024
  • $729.52 - April 17, 2024
  • $829.00 - April 1, 2024
  • $762.68 - March 28, 2024
Data source: ebay.com
Since: August 31, 2023
  • Highest Price: $829.00 - August 31, 2023
  • Lowest Price: $729.52 - April 17, 2024


Zoom on the Firman T04073

In short, the Firman T04073 is a portable generator adequately designed for:

  • RV travellers looking for even more independence
  • Occasional participants of outdoor events, competitions, concerts and festivals
  • Homeowners in need of an emergency backup power for their essentials
  • Professionals who want to be able to deliver results, even during a power failure

In the following paragraphs, we shall explore the power characteristics, available outlets, portability, and any additional features of the device.

Power & Run Time

The Firman T04073 in use

The Firman T04073

The Firman T04073 delivers 120/240V and boasts with a tri-fuel technology enabling it to utilize gasoline, propane, or natural gas. When powered by gasoline, it achieves a running wattage of 4,000W and a peak wattage of 5,000W. Upon using propane, it gains 3,600 rated watts and 4,500 peak watts. Its operation with natural gas provides 3,200W of rated wattage and 4,000W of starting wattage.

Enjoying a noise rating of 67 dBA (less noisy than a normal conversation), this generator offers the versatility of starting with either a standard recoil pull-rope starting mechanism or an easy-to-use and reliable electric starter (battery included).

Concerning its running time, the T04073, featuring a 5 gallons fuel tank, can continuously run for around 14 hours at 50% load with a full gasoline tank (consuming fuel at approximately 0.36 gallons per hour). Alternatively, when utilizing propane, it offers around 9 hours (on a 20 lbs tank - propane consumption around 0.52 GPH) of runtime.

The powering of sensitive electronic devices with the T04073 is not recommended due to its relatively high THD (<14%).


The control panel is equipped with the following 4 AC outlets:

Duplex 120V 20A (5-20R) GFCI
120V 30A (L5-30R) receptacle
120/240V 30A (L14-30R) receptacle

Even if this Firman generator isn't quite RV Ready, it still allows for an easy RV connection via an L5-30P to TT-30R adaptor (included), thanks to its L5-30R receptacle. Besides, as it features a twist-lock L14-30R receptacle, the T04073 is transfer switch ready: in case of a power outage, you will be easily able to connect it to a breaker box and power your household.


Measuring L29.8 x W27.5 x H26.1 in, the classic open frame build of the Firman T04073 delivers stability and easy maintenance access to components, facilitating air circulation. The featured design is ideal for the outdoors and all tough environments.

Even at 123.4 lbs, the generator is categorized as 'portable,' suggesting its movability, although its weight impede its portability. Nevertheless, the restricted maneuverability is counteracted by its wheel kit (⌀8") and its folding handle, enabling easy shifting once the generator is set in place.


Panel of the Firman T04073

The T04073's control panel

The T04073 and its control panel include a convenient meter, offering voltage, frequency, and lifetime hours readings. This feature comes handy when monitoring its status and activity.

In addition to this info, a light indicator serves to show you when the generator is ready.

The fuel level of the generator can be determined quickly, easily, and conveniently with the help of its built-in fuel gauge.

From a security standpoint, the generator is furnished with an overload protection (circuit breaker) and an automatic low oil shut-off, ensuring peace of mind during operation.

The T04073 also benefits from Firman’s CO Alert carbon monoxide shutdown, which automatically shuts down the engine when harmful levels of carbon monoxide accumulate around the generator or a CO Alert fault occurs.

Beyond the standard documentation and an owner's manual (opens in a new tab) to assist with setup, the Firman T04073 ships with supplementary accessories: tool kit, cover, RV adapter, funnel, oil and propane hose.

Product Video

The Firman T04073 versus other generators

The following charts are provided to give you an idea of how some of the key specs of the Firman T04073 compare to multi-fuel generators of similar power (between 3500 and 4500 W).

  • Tipping the scales at 123.4 lbs, the Firman T04073 qualifies as one of the heavier options among multi-fuel generators rated between 3500 and 4500. Regarding dry weight, one of the champions in the same power range is the WEN DF402iX, with a dry weight of only 66.1 lbs.
  • Because this generator emits noise as low as 67 dBA, it can be considered to have a pretty average expected noise rating for a device of its power. If you’d prefer a less noisy device, one of the most quiet devices, which share the same power range with this one, is the Westinghouse iGen4500DF, whose lowest noise levels reach just 52 dBA.
  • With around 14 hours of runtime at 50% load, the T04073 provides a higher run time when compared to similarly powerful inverters. If run time is one of your main concerns, the Westinghouse iGen4500DF could be worth looking at. It boasts one of the highest run times among units of comparable power, lasting around 15 hours.
  • Run time is crucial, but it heavily relies on the fuel tank's capacity. Thus, considering fuel efficiency alongside is essential. As this generator uses an estimated 0.36 GPH (gallon per hour) at a 50% load, it finds itself in the average gasoline consumption range of similar products. If minimizing fuel usage is one of your key priorities, the Westinghouse iGen4500DF is one of the most efficient devices with similar power output, with a gasoline consumption of only 0.23 gallons per hour.

Price comparison

As you can see from these interactive charts, when compared to other 3500-4500W multi-fuel generators, the Firman T04073 is on the average side of the price range.

Therefore, this generator nicely fits in the expected budget for this kind of product.

The bottom line

  • In the expected price range
  • Tri-fuel
  • CO Alert technology
  • Several accessories included
  • GFCI Outlets
  • RV adapter included
  • Electric start
  • High run time
  • Acceptable noise (67 dBA)
  • Decent fuel efficiency
  • No remote start
  • On the heavy side (123.4 lbs)

Do you own the Firman T04073 and agree (or disagree) with these strengths and weaknesses?

Let us know and write your own review.

Features and Specifications

Parallel capableNo
RV readyNo
FuelTri-Fuel (gasoline/propane/natural gas)
Engine223 cc OHV 4-stroke
Starting systemRecoil, Electric
Warranty3 years
VoltageAC: 120/240V 60 Hz
Running watts4,000 W3,600 W3,200 W
Starting watts5,000 W4,500 W4,000 W
Running amps (@120/240V)33.3/16.7 amps30/15 amps26.7/13.3 amps
Peak amps (@120/240V)41.7/20.8 amps37.5/18.8 amps33.3/16.7 amps
Run time @50% load14 h9 hN/A
Run time @25% loadUnknownUnknownN/A
GFCI outletsYes
Covered outletsYes
Automatic Voltage RegulationYes
AC outlets
  • 1x Duplex 120V 20A (5-20R) GFCI
  • 1x 120V 30A (L5-30R)
  • 1x 120/240V 30A (L14-30R)
DC outletsNo
Data centerVFT
IndicatorsOutput ready
Fuel tankSteel, 5 gal
Fuel gaugeYes
Weight123.4 lbs
Approx. dimensions (L x W x H)29.8 x 27.5 x 26.1 in
Noise (lower limit)67 dBA
THD< 14%
ComplianceCARB, EPA, ANSI/PGMA G300-2018
SecurityLow oil and overload protection, CO monitoring
Spark arrestorYes
NeutralBonded to frame
Accessories includedOil, funnel, tool kit, propane hose, RV adapter, cover, battery, and wheel kit
Country of originChina

Unlike many websites, we did our best to research each of the specs above. That being said, we are not immune to making the occasional mistake or omission. Should you notice any missing or incorrect values, don't hesitate to suggest improvements so we can address the issue.

Spec Improvement×

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About FIRMAN Power Equipment

Founded in 1999, Firman Power Equipment is a company with a short, but established history in the power equipment industry. Based in Arizona, the company offers an immense range of products, including power tools, automotive equipment, storage utilities, work wear, but most importantly, a wide selection of generators of all sizes, designs and outputs. Interestingly, Firman is a wholly owned subsidiary of the China National Machinery Industry Corporation - a somewhat well renowned company in China and acts as a de facto distributor of their products in the US.

Warranty Information

The Firman T04073 is covered under a warranty for up to 3 years. This warranty may be limited and may not cover all parts of the generator.
For more information about the warranty of Firman generators, please consult Firman's warranty policies (opens in a new tab). Alternatively, you can also contact their Customer Support: 1-844-FIRMAN1 (844-347-6261).

Questions & Answers

What can it power?
Examples of items that can be simultaneously powered.
The examples below are based on a maximum load of 80% and estimated wattages. For a more accurate estimation, use our generator sizer.
ItemRunning WattsStarting Watts
At homeDish washer15003000
AC (10,000 BTU)15002200
Refrigerator (energy star)1921192
Total3192 W4692 W
For campingRV AC (11,000 BTU)10101600
RV refrigerator180600
Hair dryer18001900
Total3190 W3780 W
For workTable saw18004500
Drain cleaner250250
Bug zapper8080
Total2130 W4830 W
Does the T4073 have a bonded neutral, and if yes, how to you make it unbonded ? (Asked May 07, 2023)

The neutral is bonded to the generator's frame. To unbond it, you may contact Firman for specific instructions, or refer to our article on bonding and floating a generator's neutral.

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