Yamaha EF2000iSv2 Inverter Generator Review

When it comes to inverter generators, Yamaha is a highly-regarded brand. It is known for its reliable and quiet engines. Yamaha EF2000iS is a particularly popular model. This inverter generator is compact and very light while providing enough electricity to power most of the common equipment: power tools, refrigerator, portable a/c unit, computer or air compressor.

Note that Yamaha EF2000iS has been replaced with a newer improved version EF2000iSV2. This review is applicable to both models, but if you are buying brand new, only EF2000iSV2 is available on sale today.

What Can EF2000iS Power?

Yamaha EF2000iS is capable of continuously producing 1600 Watt and up to 2000 Watt for short periods of time. This means that this small generator can crank our 13.3 running amps of current at 120V and short bursts of up to 16.7 amps. This is enough for most appliances and equipment, such as refrigerators, blender, electric kettle, as well as power tools like drills, saws, air compressors. Of course, check the ratings of whatever you are trying to power. If it requires less than 13.3 amps, you are good to go.

One key thing to note is that you should power only one tool or appliance at a time or a couple low-consuming appliances. Be aware that if your appliance has a heating coil it can be pretty power hungry. For example, most electric kettles require 1350-1500 Watt, which would use up most of EF2000iS’s capacity. So if you are camping and would like to have a breakfast, it is a good idea to boil your water first and then toast your bread.

If you do overload this inverter generator, it is not a huge issue, as EF2000iS will trip the circuit breaker in this case. The engine will continue running, but the electricity will stop flowing. You can simply flip the breaker back, but do not try to run the same equipment again.

With running 1600 Watt in its disposal, this Yamaha is perfect for light-duty power tool use, tailgate parties, camping, but not quite enough to power your house in case of power outage, unless you are only running your fridge and charging your phones.

How Long Can it Run?

This Yamaha can run up to 10.5 hours at 25% of its rated load or 400-Watt load. Its fuel tank fits 1.1 gallons of gasoline. Of course, if you run more power-hungry appliances or tools on it, it will run out of gas sooner.

Pulse Width Modulation

Being an inverter generator Yamaha EF2000iS produces very clean, high-quality electricity, unlike many cheaper portable generators. Yamaha claims that its pure sine wave power is as good or even better than the electricity that you get from the utilities. This is very important if you are going to be powering sensitive electronics and equipment with your generator. Yamaha promises voltage stability to stay within ±1%, and frequency stability to be within ±0.1 Hz.

Twin Tech – Parallel generator operation

If you need more power, there is an option to connect two of EF2000iS units. Yamaha sells a special cord for this purpose, which is available on Amazon. In this configuration, two EF2000iS’s can crank out up to 3000 Watt or 25 amps continuously and up to 3600 Watt or 30 amps for short periods of time.

Two 120V Receptacles and Ability to Charge 12V Batteries

EF2000iS generator comes with two 120V receptacles and 8-amp 12V output to charge car, boat or RV batteries. It also comes with a special 12V charging cable. Note that if you have a standalone battery charger that plugs into 120V receptacle, it is best to use it instead of a 12V charging cable. The reason is that battery chargers are designed to slowly trickle charge when the battery is almost full and to completely shut off when the battery is fully charged.

Is It Really That Quiet?

Yamaha EF2000iS is rated to produce noise levels of 51.5 dBA to 61 dBA when running at ¼ load. ¼ load means 400 Watt, which is enough to be powering some small appliance such as a computer.

Yamaha achieves its quietness by using Smart Throttle technology. To activate it you would need to turn on Economy Control Switch. This allows the engine to run at lower RPM, which results in fuel savings and quieter operation.

Additionally, EF2000iS is equipped with an effective noise-canceling muffler, which Yamaha claims to be their most technologically sophisticated design.

All in all, this generator runs so quietly, that you can have normal conversations beside it. Of course, when load increases and RPMs go up, this generator gets louder, but nowhere near as loud as most portable generators. Quiet operation makes it perfect for camping or tailgating, where you do not want the generator to disturb you enjoying your time.

Size and Weight

Yamaha EF2000iS is remarkably compact and lightweight for a portable generator. It weighs 44.1 lbs dry or about 50 lbs with a full fuel tank. This is light enough to be carried with one hand by most adults.

This inverter generator takes up 2.2 cubic feet of space, which means it will fit in the trunk of almost any car or truck. It is important to note that if you will be transporting this unit in the trunk, secure it well, so it does not tip over. If it tips over, the generator might burn a bit of oil for a few minutes, once you start it up.

CARB-Compliant 4-Stroke Motor

Check Price on Amazon

The heart of this inverter generator is a 79-cc 4-stroke engine. 4-stroke design means that you do not need to mix oil into gasoline. 4-stroke engines also run a lot cleaner than 2-stroke type. In fact, this unit is CARB compliant, which means you can run it in California without any problems.

The engine takes 0.42 US Quarts of 10W-30 oil. The oil is not provided when you buy the generator, so make sure to get a bottle at your local store or on Amazon. Also to fill the oil, you will need a funnel. Yamaha does not provide the funnel, but you can grab this funnel on Amazon.

The cool thing is that this generator comes with low oil indicator. So if you need to add oil, you are going to notice it right away.

Fuel Shutoff Switch

Fuel shutoff valve is a great feature that Yamaha engineers have included in this generator. Instead of simply powering off the generator, you can close the fuel valve. This will make generator run for up to a minute or two, while it burns all the gas remaining in the carburetor. This is great to reduce the gasoline smells when you are storing or transporting this unit. It also prolongs the life of the engine by keeping carburetor clean. Since most of the gasoline sold in North America contains 10% ethanol, it can have damaging effects on the jets of the carburetor.

Reviews from Owners


Check Price on Amazon

Yamaha EF2000iS has a ton of reviews on Amazon. At the time of publishing this article, this inverter generator has an average rating of 4.3 out of 5 stars out of 417 reviews. 322 of those reviews are 5 stars. Most people are amazed at how quiet and fuel efficient it is. Reviewers confirmed that this generator can run 8 to 10 hours on 1 gallon of fuel, just like Yamaha claims. People also note that this generator comes with a fuel gauge – a useful feature that most generators of this size do not have. The engine is also very easy to start, usually comes on after 1 or 2 pulls. Among negative reviews, some people have reported that this generator tends to burn oil and fuel gauge stops working. To avoid the oil burning issue, some people have suggested buying Honda eu2000i instead.

Pros & Cons


  • Super quiet operation due to advanced muffler and Smart Throttle.
  • Fuel efficient thanks to Smart Throttle and 4-stroke engine.
  • Pure-sine wave power, good for sensitive electronics.
  • Super lightweight, can be carried with one hand.
  • Small, takes up only 2.2 cu.ft. of space.
  • Starts with 1 or two pulls.
  • Robust and reliable.


  • No drain plug for fuel, need to use siphon.
  • No drain plug for oil, need to tip the unit to empty the oil into a pan, which can be messy.
  • No oil supplied with the unit.
  • No funnel supplied with the unit.
  • Some units burn oil.

Leave a Comment