Tri-Fuel kits utilize an adapter that makes it likely to work an engine on three unlike fuels; Propane, Natural Gas, and Gasoline. Adapters will combine the Propane or Natural Gas into the air stream above the gasoline carburetor. The gasoline carburetor remains mainly intact. Basically that is how the tri – fuel generators work.
So, here are some list of tri – fuel generators you should see:

Winco HPS-12000HE

This is a Honda powered tri-fuel portable generator. The HPS12000HE produces 12,000 watts of surge power and 10,800 watts of constant power. With a Honda OHV engine working on propane, natural gas, or gasoline, this generator will provide you with consistent power when you need it most. A 4-wheel dolly kit and 15 gallon fuel tank comes usual with this unit.

NorthStar Trifuel Generator

NorthStar Trifuel Generator packs 13,000 surge watts and 10,500 constant watts! It switches easily from gasoline to dry fuel without powering off and starts quick and simple in all weather. This generator has cast iron sleeve and it has an Engine Honda GX620 OHV. Rubber isolation mounts moisten vibration for even operation and gross torque is 32.5 ft-lb at 2,500. It has simple access control and outlet panel. Control panel has "push to reset" circuit breakers and run time of 10 Hours at 1/2 load. Lasting storage fuel-drain valve rapidly drains fuel for storage.

4500W Trifuel Deluxe Silent Generator (Model: DP4500EST)

This generator runs in a 7.5HP,225cc,Air Cooled, OHV,4 Stroke Engine With Low Oil Shutoff, Smooth Running, Electric starting system with EZ pull start back up. It has full enclosed heavy duty steel frame with four point fully isolated motor mounts for smooth & quiet operation. This generator runs for long 14-hour run time at 100% rated output and over 300 hours continues run with Nature Gas line or big enough LP tank with regular engine oil change & maintain. It has a 4500W surge output with gas and 4000w surge output with LP/Nature gas

Generator w/ Electric Start Honda (Model: HPS6000HE)

This generator runs in 5,500 rated watts and 6,000 surge watts. It has versatile generator runs on L.P gas, natural gas or gasoline. The generator’s engine is an 11-HP electric start Honda engine. It has premium-quality; fuel-efficient engine with low oil protection and dual element air filter reduces maintenance. This generator has a brushless alternator and its inherent voltage regulation protects electronics from surges.

NorthStar Trifuel Generator — 390cc, 8000 Surge Watts, 6600 Rated Watts

This tri-fuel generator uses engine Honda GX 390 OHV and has a gross torque of 20 ft-lb at 2,500 rpm. NorthStar Trifuel Generator packs 8000 surge watts and 6600 constant watts! It switches smoothly from gasoline to dry fuel without powering off and starts rapid and simple in all weather. This generator has cast iron sleeve. Rubber isolation mounts moisten vibration for level operation. It has simple access control and outlet panel. Control panel has "push to reset" circuit breakers. Long-term storage fuel-drain valve swiftly drains fuel for storage.

GENERATOR TRI FUEL 8,000 Watt (Model: VIR165938)

This is a 13 Hp Honda Winco 5500 watt trifuel. It is a portable power source which has a fuel type of gasoline,LP and NG made by The VirTau Company. This is has a maximum output 7.1 – 8 KW.

10000W Trifuel Deluxe Industrial Grade Generator (Model: DP10000ERT)

This generator runs in a 16.0HP, 420cc, air cooled, OHV, a 4 stroke engine with low oil shutoff, smooth running, EZ pull starting & E-start. It has a heavy duty steel frame with four point fully isolated motor mounts for smooth & quiet operation. This generator runs for a long 16-hour run time at 100% rated output and over 300 hours continues running with Nature Gas supply or big enough LP tank. It has a 10000W surge output with gas and an 8500W surge with Propane/Nature Gas.

9 kW Tri-Fuel (Gas, Propane, Natural Gas) Portable Generator - Winco

(Manufacturer item no: HPS9000E)
Winco Home Power Tri Fuel portable generator keeps you away from the dark. The Made in the USA unit operates on gasoline, LP gas (propane), or natural gas, and converting one fuel source to another can be accomplished rapidly and effortlessly. The HPS9000E is powered by a premium-quality 16 horsepower Briggs & Stratton engine and is enclosed by a distinguishing wrap around steel cradle for power and robustness.