Yamaha EF2000iS Review

Yamaha EF2000iSYamaha inverter generators are among the most highly-regarded, and for good reason. And the EF2000iS is the model of choice for many people, especially those seeking a very small, but still quite powerful unit that can provide some small measure of backup power in addition to recreational power.

However, there are other things to consider before seriously considering a purchase, besides its sheer popularity.

Please read our in-depth review to learn more about the EF2000iS, and what we think about it.

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Engine Displacement & Power Output

The EF2000iS uses a 79 cc 4-stroke OHV engine that is very high quality. It’s fitted with a cast iron cylinder as well, which enhances its efficiency and engine life, with superior heat dissipation compared to other small inverter engines.

This model generates a total of 2000 surge watts 1600 running watts. And because it’s an inverter system, and comes with Yamaha’s Pulse Width Modulation (PWM) control, this generator will produce a very “clean” – i.e., pure – sine wave that is ideal for running anything from an air conditioner to the most sophisticated and sensitive electronics.

With 1,600 running watts, the EF2000iS is not really the most effective emergency power source. However, if you only need to power a couple large appliances, like a full sized fridge and perhaps a small air conditioner – or a sump pump, lighting and a few other smaller appliances, then this model might do the job. For a better idea of what 1,600 watts will get you during an outage, check out our Generator Sizing Calculator.

Runtime & Fuel Type

This inverter generator comes with a small, 1.1 gallon gas tank that takes regular unleaded. However, despite this small tank, the EF2000iS can run for 10.5 hours when under a 25% load. This is a great runtime for an inverter and confirms how fuel efficient this model is relative to the field.

Start Type

A simple pull start mechanism is used and, as discussed below, is legendary for its reliability – generally starting on the first pull, even when first cranked after coming out of the box.

Yamaha EF2000iS3Panel Outlets

  • (2) 5-20R outlets
  • (1) 12v DC (charging) receptacle

Noise Level

Yamaha inverters and the EF2000iS are legendary for their quiet running. This model is fitted with Yamaha’s most cutting-edge muffler system that results in noise levels of 51.5 dB to 61 dB. This is truly whisper quiet – so quiet in fact that most people will not know this unit is running until you get quite close to it.

Given this ultra-low noise level, it’s not surprising that the EF2000iS is one of the most popular camping generators out there.

Size & Portability

Another huge feature of the EF2000iS and what sets it apart from the pack is its compact size and light weight. This model is only 44 pounds when dry and occupies a 2.2 cubic foot space (i.e., 19.3 in long, 11.0 in wide and 17.9 in high).

With this kind of true portability, the EF2000iS is a pleasure to carry and take virtually anywhere – yet another reason why the recreational-use crowd love this model.

Product Warranty

Also a standout is the EF2000iS‘s excellent manufacturer’s warranty –  a 3-year warranty that applies to the entire generator and covers it for defects in parts and workmanship.

Price & Value

If there is one downside to having all of this build quality, portability and nearly silent operation, it’s price. Inverter generators are overall much more expensive than their conventional counterparts watt for watt, but the Yamaha models are particularly pricey, even by inveter standards. Specifically, the EF2000iS is currently selling for about $1,000, which means that it provides only 1.6 running watts per dollar of purchase price.

Of course, this is still better than the more expensive and similarly-rated Honda EU2000i; however, it is significantly less than other inverters hitting the market these days. For a comparison of this model’s output vs. price relative to other popular inverters, check out our Ultimate Comparison Buying Guide.

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Yamaha EF2000iS2Yamaha EF2000iS Reviews & Ratings

Perhaps the most telling thing about the Yamaha EF2000iS is just how loved it is by purchasers. In fact, we have not seen such praise, across so many reviews, for any other inverter generator.

Specifically, the EF2000iS has earned 4.7 of 5 stars out of 165 amazon reviews. And while this is itself extremely impressive, what’s even more interesting is the distribution of these scores:

ScreenHunter_09 May. 11 18.45

As you can see, 138 of these reviews – nearly 84% of them – are full 5-stars, with the remaining 14% (or 27 reviews) being 4-star or less. This is pretty amazing; we rarely see products with so many five-star reviews.

As you could imagine, in a nutshell, people were blown away by how quiet, reliable and portable this unit is. And in particular, many reviewers noted how easily and reliably this generator started on the very first pull, time and time again.

Moreover, among those relatively few negative reviews, most resulted from isolated product defects or unrealistic user expectations. For example, one negative commenter gave the EF2000iS low marks because it was underpowered for an emergency power generator – even thought that’s not what it’s designed for. As we always say, your power needs are something that must be understood before buying any generator, particularly when considering a small, highly-portable inverter generator.

Read The Full Yamaha EF2000iS Reviews Here!


Super quiet!
Very fuel efficient
Legendary reliability
Extremely lightweight & compact
Good runtime
Great factory warranty
Produces very “clean” electricity


Limited power output

Additional Features

  • fuel gauge
  • gasoline petcock
  • voltage selector switch
  • parallel function – connect two generators together to double power
  • low oil warning system
  • EPA & CARB-approved
  • spark arrestor
  • smart throttle (automatic throttle adjustment)
  • auto warm up – boosts engine speed during cold start
  • auto decompression for quick starting
  • overload circuit breakers
  • DC 8A/12V charging outlet
  • 3 year warranty (on entire generator for defects in parts & workmanship)

We’re happy to note that this model is CARB-approved and can be sold in all 50 states, including California.

Yamaha EF2000iS1Concluding Thoughts & Opinions

In our view, if you want a generator that you can use for camping or other recreational uses and, perhaps, support one or two larger appliances when emergency power is needed, the EF2000iS is one of the best and most reliable inverter generators you can buy. In particular, its fuel efficiency, quiet operation, and incredibly light weight make it a superior choice for those looking to travel with their power source. Moreover, from a quality and reliability standpoint too, Yamaha inverters are considered second to none, with the closest competitor being Honda.

Nevertheless, we would definitely not consider this a good emergency power source for most people. if you are buying a generator mostly for backup power to keep you going through outages, then most people with either need a much bigger Yamaha inverter, or a conventional generator that will deliver a lot more raw power for greedy appliances like sumps, fridges AC units, heaters, etc.

Finally, even though the EF2000iS is very expensive compared to virtually all other generators, save the Honda models, we’d still consider it a good buy if you can afford it. The reason is that the EF2000iS is just so well-built and reliable – when you consider the many years of service it can provide, it’s definitely worth the relatively higher price tag in our view.

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  1. Gilberto Castro says:

    Hello Rick! I am in Puerto Rico and a very happy owner of a Yamaha 2000si. I purchase mine for my boat, but never had the need to really use the Yamaha. After hurricane Maria, September 21, 2017, I have been running my Yamaha generator 12 hours each day. I added a second generator and run one at a time, a full tank, so when one goes out of fuel, the second comes in, and it goes like that 24 hours a day, for ever…. I do change the oil every 5 days, and do the require maintenance, but these little generators always start and run like the first time. It’s being 33 days so far and they are going strong. No regrets!!!!!!!!!!!!!!!!!!

  2. Darla Shreffler says:

    Can this generator run in parallel with the Yamaha SC2000i?

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