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Compare Generators Side-by-Side

Select up to 4 generators to compare specs, power output, noise levels, runtime and more. Your compare URL is shareable.

  • Firman T04073
  • Cat RP6500 E
  • Model T04073
    Model T04073

    Firman 4,000W Tri-Fuel Generator

    4000W
    Running
    67 dB
    Noise
    View details
  • Model RP6500 E
    Model RP6500 E

    Cat 6,500W Gas Generator

    6500W
    Running
    0 dB
    Noise
    View details
Quick charts
Each chart uses its own Y-axis scale (so numbers are comparable within a chart).
Running watts
W
Starting watts
W
Noise
dB
Runtime @50%
h
Running watts by fuel
Shows how output changes across gasoline/propane/natural gas (when available).
Generator Specifications Comparison
SpecificationFirman T04073Cat RP6500 E
General
Product type
Generator
Generator
Fuel
Tri-Fuel
Gasoline
InverterNoNo
Parallel capableNoNo
RV readyNoNo
Running watts
4000 W
Winner: Winner: 6500 W
Starting watts
5000 W
Winner: Winner: 8125 W
Noise (lower limit)
Winner: Winner: 67 dB
0 dB
Weight
Winner: Winner: 123.4 lbs
202 lbs
Run time @50% load
Winner: Winner: 12 h
Winner: Winner: 12 h
Run time @25% load
14 h
Not available—
Fuel tank
5 gal
7.9 gal
Fuel gaugeYesYes
Approx. dimensions (L × W × H)
29.8 x 27.5 x 26.1
32.9 x 27.4 x 24.7
Electrical
Voltage (AC)
120/240
120/240
Voltage (DC)
Not available—
Not available—
GFCI outletsYesYes
Covered outletsYesYes
Automatic Voltage RegulationYesYes
THD
11%-14% %
Not available—
Engine
Engine
223 cc OHV 4-stroke, cast iron sleeve
420 cc OHV 4-stroke
Alternator
Not available—
Not available—
Starting system
Recoil, Electric
Recoil, Electric
Warranty
Warranty
3 years
2 years
Power by fuel
GasolineNot available—Not available—
Running watts
4000 W
6500 W
Starting watts
5000 W
8125 W
Running amps (120V)
Not available—
Not available—
Running amps (240V)
Not available—
Not available—
Peak amps (120V)
Not available—
Not available—
Peak amps (240V)
Not available—
Not available—
Run time @50% load
14 h
12 h
Run time @25% load
Not available—
Not available—
Natural gasNot available—Not available—
Running watts
3200 W
Not available—
Starting watts
4000 W
Not available—
Running amps (120V)
Not available—
Not available—
Running amps (240V)
Not available—
Not available—
Peak amps (120V)
Not available—
Not available—
Peak amps (240V)
Not available—
Not available—
Run time @50% load
Not available—
Not available—
Run time @25% load
Not available—
Not available—
PropaneNot available—Not available—
Running watts
3600 W
Not available—
Starting watts
4500 W
Not available—
Running amps (120V)
Not available—
Not available—
Running amps (240V)
Not available—
Not available—
Peak amps (120V)
Not available—
Not available—
Peak amps (240V)
Not available—
Not available—
Run time @50% load
9 h
Not available—
Run time @25% load
Not available—
Not available—
Other
Data center
Not available—
Not available—
Indicators
true
false
Compliance
CARB, EPA, ANSI/PGMA G300-2023
CARB, EPA
Security
Not available—
Not available—
Spark arrestorYesYes
Neutral
true
true
UPC
840876140734
815683020067
Core / High-priority specs
Running Watts (Gasoline)
4000
6500
Running Watts (Propane)
3600
Not available—
Running Watts (Natural Gas)
3200
Not available—
Starting Watts (Gasoline)
5000
8125
Starting Watts (Propane)
4500
Not available—
Starting Watts (Natural Gas)
4000
Not available—
Runtime @ 50% Load (Gasoline)
14
12
Runtime @ 50% Load (Propane)
9
Not available—
AC Outlet Types
1x Duplex 120V 20A (5-20R) GFCI; 1x 120V 30A (L5-30R); 1x 120/240V 30A (L14-30R)
2x Duplex 120V 20A (5-20R); 1x 120/240V 30A (L14-30R); 1x 120V 30A (L5-30R)
Electrical & power
Frequency
60
60
Engine & construction
Engine Type
223 cc OHV 4-stroke
OHV 4-stroke
Engine Displacement
223
420
Cylinder Sleeve
cast iron
Not available—
Engine Oil Type
Not available—
SAE 30 or 10W-30
Runtime & fuel system
Runtime @ 50% Load (Gasoline)
14
12
Runtime @ 50% Load (Propane)
9
Not available—
Safety & compliance
Overload Protection System
Low oil and overload protection, CO monitoring
Low oil and overload protection
Low Oil ProtectionYesYes
Carbon Monoxide MonitoringYesNo
Included equipment
Starting Components
Recoil, Electric
Recoil, Electric
Included Accessories
Oil, funnel, tool kit, propane hose, RV adapter, cover, battery, and wheel kit
Oil, funnel, tool kit, battery, and wheel kit
Warranty & identification
Commercial Warranty
3
Not available—
Part Number
Not available—
502-3688
Additional specs
Summary
The Firman T04073 is a 4,000-watt tri-fuel generator that runs on gasoline, propane, or natural gas. On gasoline, it delivers 5,000 starting watts and 4,000 running watts, enough to power a refrigerator, microwave, and multiple household circuits simultaneously. On propane, output drops to 3,600 running watts, and on natural gas it falls to 3,200 running watts. This fuel flexibility means users can switch between sources based on availability and cost, a significant advantage during extended outages or in remote locations where one fuel type may be scarce. The T04073 targets homeowners, RV owners, and job site operators who need reliable backup power without the commitment to a single fuel source. Its 5-gallon tank runs for 14 hours at 25% load on gasoline, translating to roughly one week of emergency backup if you run it a few hours per day. The unit includes a wheel kit, making it easier to position despite its 123.4-pound weight.
The Cat RP6500 E is a 6500-watt gasoline generator built for residential backup and light commercial work. Its 8125-watt peak capacity means it can start large tools and appliances that draw high inrush current, then sustain 6500 watts of continuous power for multiple devices simultaneously. A 7.9-gallon fuel tank delivers 12 hours of runtime at 50% load, which translates to roughly one full workday or overnight backup without refueling. The gasoline engine is straightforward to maintain and refuel anywhere, making this unit practical for job sites, outdoor events, and emergency home power.
  • Most Powerful
    Cat RP6500 E
    6500W running
  • Quietest
    Firman T04073
    67 dB
  • Longest Runtime
    Firman T04073
    12h at 50% load
Where to buy
Prices can change. We update these automatically.
Firman T04073
Store links
No links yet.
Cat RP6500 E
Store links
No links yet.
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