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WEN

WEN GN400i RV-Ready 4000-Watt Open Frame Inverter Generator, CARB Compliant, Black/orange

Based on 1,062 reviews
Condition: New
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$447.51
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Availability: 15 left in stock
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Arrives Nov 18 – Nov 22
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At a glance

Condition
New
Style
4000W Inverter
Model
GN400i
Dimensions
19.8"L x 13.8"W x 18.9"H
Color
Black/orange
Wattage
4000 watts
Fuel Type
Gasoline
In the box
Inverter generator with two 120V NEMA 5-20R receptaclestwo 5V USB portsone 120V RV-ready TT-30R receptacle

Features 5

  • Dimensions: 19.8" L x 13.8" W x 18.9" H | Weight: 66.1 lb.amperage : 26.6 amps
  • Generate clean power to safely operate sensitive electronics such as phones, tablets, televisions and computers
  • Parallel-ready panel allows you to connect any two WEN inverter generators for increased wattage output
  • 212cc 4-stroke CARB-compliant OHV engine produces 4000 surge watts and 3500 rated watts

Description

Remember when you had clean and quiet portable power? The WEN 4,000-Watt Inverter Generator provides clean energy, free of voltage spikes and drops for safe use with laptops, phones, and other sensitive electronics. Our 212cc 4-stroke OHV engine produces up to 4000 surge watts and 3500 rated watts of power. Designed to mirror a pure sine wave, this generator limits total harmonic distortion to under 0.3 percent at no load and under 1.2 percent at full load, making it safe to run sensitive electronics. Our ultra-efficient 1.85-gallon tank provides over 7 hours of half-load run time. The fully-packed panel comes equipped with two three-prong 120V NEMA 5-20R receptacles, two 5V USB ports, and one 120V RV-ready TT-30R receptacle. Maximize fuel economy by engaging the eco-mode switch. This allows the generator's engine to automatically adjust its fuel consumption as items are plugged into and unplugged from the panel, preventing the unnecessary usage of gasoline. Need more energy? Easily link up two generators using a WEN Parallel Connection Kit (sold separately) in order to share wattage amongst multiple units. Low-oil and low-fuel automatic shutdown combine with the built-in overload protection and indicator lights to safeguard both your generator and your electronics from damage. And because its a WEN product, your open frame inverter generator comes backed by a two-year warranty, a nationwide network of skilled service technicians, and a friendly customer help line, all to make sure you remember WEN.

Specs 33

Brand WEN
Wattage 4000 watts
Fuel Type Gasoline
Power Source Gas Powered
Recommended Uses For Product Residential, Recreational
Voltage 120 volts
Output Wattage 4000 watts
Special Feature Portable

Frequently asked questions

If you place your order now, the estimated arrival date for this product is: Nov 18 – Nov 22

This item is non-returnable:

Non-returnable. Transportation of this item is subject to hazardous materials regulation

View our full returns policy here.

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Top Amazon Reviews

A gem of a Inverter Generator
Style: 4000W Inverter
I was looking for a emergency home generator and looked high and low for one that used inverter technology. I was concerned as a neighbor bought a generator without a inverter and ruined a refrigerator and TV beyond repair. His generator was a 4000 watt unit at the same price point as the WEN. While I can’t speak for the construction the WEN appears better finished and more solid. Both weigh about the same. Both are open framed. The setup is like any new engine, read the manual. I did use Pennzoil Ultra 10/30 Synthetic oil, Premium gas with one ounce of Lucas Oil Treatment as I had good luck with the combo in my lawnmower, car and motorcycle. Absolutely no problems with set up and breaking in the WEN. There is a grounding wire tap on the control panel which I did attach to ground the generator as it was close to our main water inlet. Grounding the generator makes sense as electronics are extremely sensitive! An ounce of prevention now can save hundreds or thousands latter. My installation is in a home. I know nothing about use in RV’s or campers, but would think a ground makes sense there too. For me the WEN is an affordable and so far reliable Inverter generator! I think it’s a steal! Thinking of buying another so as not to stress out a single unit in long periods of use. Addendum: It’s been over a year and half now and the WEN is still doing its thing without problem. I installed an Hour Meter and accumulated 247 hours. I’ve changed the oil every 48 hours, installed a magnetic drain plug and a new spark plug if it look fouled. I still use Lucas Oil Treatment one ounce at each oil change. I bought a second WEN and now run them in parallel without any problems. The pair can run a 12,000btu a/c, full size refrigerator and a 1000 what microwave. I do turn the a/c to fan when using the microwave as not to stress the generators. No failures, starts with one or two pulls, very little smoke and have not noticed any change in noise levels. It’s easier to move two 60+ pound generators than one 8,000 watt unit. My volt meter shows a steady output. With load shows 6,700 watts steady and peak of 7,250 watts in parallel and 3,320 watts as a single unit steady state. ... show more
Reviewed in the United States on June 11, 2022 by alan fenick
I Really Like This Machine !
Style: 4000W Inverter
The video sounds like the generator is much louder than the electric leaf blower it is powering but they are dang near the same annoyance level , oops I mean decibels (the blower was metered once and came in at 65db from 3' away fwiw) . Ok now that that is out of the way the things I REALLY appreciate about those one vs my old Homelite 5k watt machine . It's pretty much apples to bananas but they're both fruit. The Wen was not light but I easily carried it the 100 feet to the place I store it at when I was done vs getting my buttocks kicked rolling the old one across the yard to put it away. Even easier was the amount of oomph it took to start it up. It was evenly stressing to pull the cord to start my Lawn Boy push mower , which is a dream to pull . It started on its maiden run on the second pull and the choke was ready to disengage as soon as I let the cord go. From the box the eco mode is not on and with no load there's quite a difference in rpms (meaning gas consumption is less as well as noise ) once it's engaged. I was really surprised at how much it dropped in rpms when I engaged it . Again my old Homelight ran 1 speed , high , and was insanely loud to boot. The layouts of both aren't all that dissimilar and about the same distance from the ground (gotta bend over pretty far too reach them ) but the Wen has more options that I probably won't use , like the usb ports , and only 2 120 plugs vs 4 on the Homelite . I never ran more than 2 cords off the Homelite so that's a wash. The Wen made no discernible change when I plugged my phone charger and phone but did ramp up when I plugged in my Keurig and turned it on. To be honest the weirdest thing was when I used my leaf blower. When I turned it on that seemed to tax the generator hardest for a split second when econo mode was on and it sounded like a generator does (that loud spurt then normal noise ) but when it was off it made only a slight noise and rpm rise . Nothing else I tried caused that effect . The only thing I do not looks about this generator is the oil fill. It's almost horizontal and just invites trouble and a mess . You've got a round dipstick that twists out but you're trying to read a flat side of it . That makes no sense to me .Filling the oil was just as cumbersome and I probably spilled 2 or more ounces when I filled it only to find it wasn't quite level and when I put it perfectly level about 1/2 am ounce came out the front. I don't see under fill as a potential problem but over fill is another story . For over a decade I ran a goliath machine that drank over a gallon per hour of gasoline and annoyed neighbors for blocks around so I never ran it longer than it needed . Not to mention the extreme chore it was to pull it out, get it running , then put it away when done I used to loathe that 1/4 year when it was time to run it to keep things going as best as it could (never did run quite right ) I was almost glad when I put gas in the tank and it just poured out over the ground . Sucked not having a generator for a while but I also only needed it once (the day it failed ) and I've taken a HUGE step up in quality and to be honest it won't be a pain to test it monthly if it continues to run so smoothly and start so readily. 67 pounds vs 167 pounds on top of that . I only put a quart of gas in the tank ,I tested stuff , let it run, etc and after a hour I still had to turn off the fuel to the carburetor to get it shut down without leaving anything in it . With the Homelite there's no way that little bit of gas could have done that much . Some of the smaller sized inverters might have sufficed for my needs ( fridge , coffee pot , fish tank filter and heater and a couple of 3 amp wall warts to charge the power banks back up ) but I am glad I got this one in case my needs change . ... show more
Reviewed in the United States on March 26, 2021 by Stephen Elmore
GN400i - So far so good
Style: 4000W Inverter
FUNCTION- Pros: I bought this for my RV and for backup power in case of a power outage. The gn400i has a lot of bang for the buck. At 4000 peak/3500 rated watts, it should service my purpose well. Love having the 30 amp receptacle. Love the fact it is an inverter generator. It seems to run strong, pushing a 1500 watt heater without missing a beat....and that was in eco mode. This generator is also very economical. My 7+ hours of run time was on a 2/3-3/4 full tank. A full 1.85 gallons should last a long time. At 66lbs it is also light enough to move around. I can lift it into the bed of a truck with ease. Cons: While perfect for an RV, it's a little weak for running a household. I'll be plugging and unplugging a whole bunch during an outage. NOISE- Let's address the elephant in the room Pros: At least it isn't as loud as a Harley??? If you have an RV, then you know the a/c's are extremely loud and will drown out almost anything. I don't think noise will be an issue except maybe with a neighbor. I also have a long extension cord, so I can move the generator far away from the RV to reduce noise. Cons: This generator is LOUD. Period. I read somewhere that it was rated at 67dba. Where? It isn't in the manual. When I first started this thing, my first thought was there is no way this is in the 60's. According to my phone app, it was over 80dba next to the unit and between 72-76dba at about 20 feet. There is very little difference in noise between eco/regular mode. MAINTENANCE/BREAK-IN- Pros: This open frame generator is SO much easier to work on than my last Champion 2000 inverters. Everything is more accessible. Even with the panels off on the Champions, space was very limited for you hands. Wen was very thoughtful when designing the GN400i for service. Oil changes are easy....keep reading to see why that is important. And the fact they include an elevation kit and a handy dandy funnel is a real plus, too! Cons: After prepping the unit with Mobil 1 5w-30, I ran for 30 minutes and did an oil change. The magnetic dipstick was caked with shavings and the oil itself was black with lots of metallic specks. I've had motorcycles, atvs, lawn mowers and 3 other generators. I've never seen oil that dirty. I ran another 4-5 hours and changed the oil again. Again, it was black but at least without the metallic specks. After 7 hours, the oil looks decent but the dipstick is still coming out black. I'll likely change oil again at 10-15 hours. All this to say, if you buy one of these plan on 3-4 oil changes during the initial break-in to flush the engine prior to regular use. EDIT: After sitting unused for 6 months (Sep 2021), fired right up. Runs one of my 15k btu a/c's in my 5th wheel just fine (one unit, won't run both). Still happy. EDIT2: First Power Outage since I purchased. Pulled the generator out after sitting another year in storage (Oct 2022). Started on the 5th pull. Purred like a kitten while running my 2 refrigerators. EDIT3: Dry camping trip coming up. Got out to make sure it would fire up. Started on 2nd pull. (April 2023). Strongly recommend Stabil and running the fuel out of the carb. Put about 30 hours on it. Ran like a champ! Edit: Feb 2025. Haven't had much reason to use the genny over the past 22 months. Decided I would run it a while this morning. Started on the 5th pull. Running a space heater. Purring like a kitten. ... show more
Reviewed in the United States on March 3, 2021 by JB
Just buy the damn thing!
Style: 4000W Inverter
So I did my home work etc. That doesn't mean much... Bought it and was packed well. The colors of the unit and fit and finish are excellent. It's small enough foot print and light enough I can carry it myself and out in my back seat of the car. Started 2nd pull, did a bit of a break in. Monitored temperatures with my thermal imager. Even the Inverter is forced air cooled by the engine. Ran PERFECT. Started a large load which was a 24 amp running air compressor while charging power tool batteries-5 of them. You know I had to test it once loosened up a bit. Using a killawatt meter and a true RMS meter, she delivers big. 60-60.1 hrtz and stable voltage. I have never seen power this clean from line power, a generator or even a pure sine wave inverter. I'm blown away no bs. This little thing has beyond impressed me. I am picky and expect everything to be junk as a industrial engineer/mechanic. But my concerns have been proven not needed. I don't care who you are, what you think you need to run-this is something everyone should have . What a great little machine. It's the Hercules of generators. Good warranty, parts are cheap and available from the manufacturer. I have a Honda units that can't perform this clean or strong. Whoever designed this, I hope you are doing very well and are retired. A work of art. And the price! FFS lol. Well done Wen. ... show more
Reviewed in the United States on July 15, 2023 by tom
Easy setup and seems to be reliable
Style: 4000W Inverter
Easy setup, instructions were very clear and detailed. Generator is about 60-pounds, factory packaging was balanced and easy to move around. Open frame design makes it more convenient to move around, but I still had a friend or trustworthy foe on-call in case I needed it. Generator comes with 3 carb jets for different altitude ranges. The jet for sea-level to 3k ft is installed, 3k-6k and 6k-8k are in little zip-lock bags in the tools/parts bag. A small label is on the little zip-lock that says the altitude range for the jet, I'd recommend putting something in the zip-lock to show the altitude range. Instructions for changing the jets are included in the generator manual and in the little bags for the jets. Everything was included except fuel, oil, and the grounding equipment. Fuel is unleaded, 87 octane, holds about 2 gallons. Oil is .5L (a little over 2 cups or 1 pint). For grounding, I used a set of jumper cables and a piece of rebar for mobility. It started on the 2nd pull, ran smoothly. I didn't notice exhaust, although it was running outside on a windy day. It was louder than I expected, I couldn't have a normal conversation next to it. About the same noise as a gas lawnmower. Good generator, lots of available power. I'd get another if I need it. ... show more
Reviewed in the United States on July 17, 2022 by M. J. WELCH
Started on first pull!
Style: 4000W Inverter
Purchased for the rolling power outages in Northern California. Was delivered quickly and courteously! I Read the manual (yep!), unpacked, removed the shipping brackets, filled with 5w-30 Mobil1 (30w conventional is also acceptable for my temp range) and premium fuel. I pulled the starter rope 6x without turning on the fuel valve to distribute the oil a bit (my original intent was only to pull it 2-3x with ignition off but I neglected to turn on the fuel valve DOH), turned on the ignition switch, re-set the choke, brought the piston to the compression stroke, gave a sharp pull and it fired up on the first pull! I ran it for approximately 20 hours over three days (4 + 12 + 4) with the following load: Outlet 1 (115v 15a) 1 - side-by-side refrigerator/freezer 1 - mini fridge Outlet 2 (115v 15a) 1 - 44" LCD TV 1 - Cable DVR 1 - Cable Modem 2 - Charging stations for phone / laptops 1 - 38" LG LED computer monitor 2 - tower PCs with spinning disks (6) 1 - Network Switch 1 - Floor lamp with 10w LED bulb All in all, once everything came up to power and settled, I was able to run the generator in "Eco mode" (2400W and below running load), greatly reducing the noise level. If this were not an open-frame generator, I think it would be a little quieter, but it's not bad at all! When the fridges were first brought on line, it took a while for the load to settle down to something reasonable, as they were without power for 24hours at that point. A note that even in ECO mode, it will automatically increase generator output as needed, but to run above 2400W continuously it's recommended to turn off ECO mode. All-in-all a solid purchase. I would definitely recommend and purchase again! ... show more
Reviewed in the United States on November 3, 2020 by Jeff F.
Versatile Generator at Reasonable Price
Style: 4000W Inverter
Wanted a generator for multiple purposes, power outages, run electric tools too far from outlets, run tools for a home build, and power an rv when necessary. Decided on this model and power range to power the necessities during a power outage but still be small enough to move around easily. Came in very handy a few days after it arrived when we lost power for 8 hours, then again a day later for 4 hours. Run time on fuel might be exaggerated just a bit but did seem quite good. Not as quite as some inverter generators, but was much quieter than my neighbors around me with their "whole" house generators surging up and down frequently. Just a little on the heavier side for me at 64 and maybe losing a step, but I put it on a small dolly and it rolled around easy. Very easy and simple starting. So easy to transport I used in the back of my truck to power a tree limb trimmer to clean up after snow and wind had taken down lots of trees. You won't be disappointed! ... show more
Reviewed in the United States on February 3, 2023 by Tim
GN400i
Style: 4000W Inverter
Review Image by Marilyn G.
Review Image by Marilyn G.
This generator has been incredible. Bought in 2021, I added an hour meter before the first start. This generator now has over 3,000 hours on it (last pic I took of the meter was at 2,716). I use the generator to power our house at our hunting camp. We run the generator 24 hours a day for days on end. It never skips a beat. I made sure to break the engine in carefully changing the oil frequently. We now religiously change the oil every trip, or 100 hours if the generator is going to be running for more than 100 hours in a single trip. It has run in 110+ degree heat, rain, and freezing temps. It is very fuel efficient, I use a 15 gallon portable fuel tank connected directly into the fuel line on the generator and get 2.5 - 3 days of runtime, dependent upon the load. ... show more
Reviewed in the United States on January 25, 2026 by Marilyn G.
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