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Yamaha EF1000iS Spec Review

The Yamaha EF1000iS is a quiet, compact and lightweight portable inverter generator with a rated wattage of 900 W and a starting wattage of 1000 W.

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Picture 1 of the Yamaha EF1000iS
Picture 2 of the Yamaha EF1000iS
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Description

SMALL BUT MIGHTY. Quiet, fuel efficient, and power clean enough to run sensitive electronic equipment all in a portable 28‑lb package. (source: Yamaha (opens in a new tab))

Zoom on the Yamaha EF1000iS

In summary, the Yamaha EF1000iS is a quiet, compact and lightweight portable inverter generator especially useful for:

  • Camping and tailgating hobbyists looking for a portable power source
  • DIYers who wish to improve their efficiency with tools

In the sections ahead, the power characteristics, availability of various outlets, the portability, and any additional features of the device shall be discussed, including its emission compliance information.

Power & Run Time

The Yamaha EF1000iS in use

The Yamaha EF1000iS

The Yamaha EF1000iS houses a 50 cc Yamaha MZ50 OHV 4-stroke engine, which provides 120V, consumes gasoline and delivers a running wattage of 900W along with a peak wattage of 1000W.

With a noise rating of 47 dBA (less noisy than bird calls), the inverter generator features a simple traditional pull-start mechanism.

This generator features Yamaha's Smart Throttle™. This load-sensing feature automatically adjusts engine speed to match its load in order to offer greater fuel efficiency and noise reduction.

The EF1000iS can operate for up to 11.9 hours with a full tank (fuel consumption around 0.06 GPH), due to its fuel capacity of 0.66 gallon.

The EF1000iS generates a clean sine wave: providing <2.5% Total Harmonic Disruption (THD), delicate electronics can be plugged in its AC outlets safely.

Outlets

The control panel provides the upcoming 2 AC outlets:

Duplex 120V 15A (5-15R)

It also sports 1 DC outlet: there's a 12V 8A receptacle with which charging your batteries is made easy.

Portability

Since the Yamaha EF1000iS is an inverter generator, its closed design (L17.7 x W9.4 x H14.9 in) has an esthetical advantage over conventional, open frame devices. This type of design is the most modern and convenient way to recreationally generate power.

With a weight of only 27.9 lbs, the EF1000iS may be viewed as a lightweight and portable generator. As it can be moved by a single person without much effort, the generator and its power can be enjoyed on-the-go. This convenience is further enhanced thanks to its handle (molded in the case) that allows you to carry it with ease.

Good to know: This unit ranks 5th in our list of the 10 smallest portable generators.

Features

Panel of the Yamaha EF1000iS

The EF1000iS's control panel

When the oil level is too low, the generator is on overload and the generator is ready, you will be informed by the featured light indicators.

From a security standpoint, the product offers an overload protection (circuit breaker) and an automatic low oil shut-off (Oil Watch system), allowing you to use it with a peace of mind.

Yamaha's Oil Watch warning system gives you an extra peace of mind. This feature enhances long-term durability by preventing engine damage and costly repairs. Once the oil begins to run low, the generator automatically shuts off and cannot be re-started until oil is added.

Regarding its accessories, besides the aforementioned features, the Yamaha EF1000iS's box includes the typical documentation and an owner's manual (opens in a new tab), letting you start it right off the bat.

Emissions

The Yamaha EF1000iS is EPA-approved and CARB-compliant. Therefore, its sale and purchase are permitted in all of the 50 states, including California.

Moreover, it features a spark arrestor, making it usable in forested areas.

Product Videos

The Yamaha EF1000iS versus other generators

The following charts are provided to give you an idea of how some of the key specs of the Yamaha EF1000iS compare to generators of similar power (between 500 and 1500 W).

  • As far as its dry weight is concerned, the Yamaha EF1000iS weighs just 27.9 pounds and thus, it is one of the lighter 500 to 1500 rated wattage generators. In terms of weight, one of the champions in their power range is the Sportsman GEN1000i, standing at just 20.3 lbs.
  • With a lowest possible noise of 47 dBA, this inverter generator places itself amongst the more quiet of the products delivering similar power. If noise emissions are one of your priorities, you may be interested in the Honda EU1000i, one of the least noisy generators similarly powerful as this one, rated for 42 dBA.
  • As the EF1000iS features an autonomy of up to 11.9 hours at 25% load, it has one of the highest run times in comparison to the other generators of its power range.
  • While the run time is an important parameter, it is dependent on the fuel tank’s capacity and thus, doesn’t say much on its own unless we consider fuel consumption as well. At an estimated fuel consumption of 0.06 GPH (gallon per hour) at 25% load, this inverter generator is one of the most fuel efficient units within its wattage category.
According to our stats, the following comparison is pretty popular: Yamaha EF1000iS vs Honda EU1000i.

Price comparison

As you can see from this interactive chart, when compared to other 500-1500W generators, the Yamaha EF1000iS is on the expensive side of the price range.

While certainly not the cheapest of its kind, purchasing it would most likely also mean enjoying the reliability of a high-end product.

The bottom line

STRENGTHS:
  • Inverter
  • Lightweight (27.9 lbs)
  • Quiet for its power (47 dBA)
  • High run time
  • Fuel efficient
WEAKNESSES:
  • On the expensive side
  • No data center
  • No electric start
  • No parallel ports

Do you own the Yamaha EF1000iS and agree (or disagree) with these strengths and weaknesses?

Let us know and write your own review.

Features and Specifications

General
InverterYes
PortableYes
Parallel capableNo
RV readyNo
FuelGasoline
Engine50 cc Yamaha MZ50 OHV 4-stroke
Starting systemRecoil
Power
VoltageAC: 120V 60 Hz, DC: 12V
Running watts900 W
Starting watts1000 W
Running amps7.5 amps
Peaks amps8.3 amps
Run time @50% loadUnknown
Run time @25% load11.9 h
Features
GFCI outletsNo
Covered outletsNo
Automatic Voltage RegulationInverter
AC outlets1x Duplex 120V 15A (5-15R)
DC outlets1x 12V 8A receptacle
Data centerNo
IndicatorsLow oil, overload and output ready
Fuel tank0.66 gal
Fuel gaugeNo
Misc
Weight27.9 lbs
Approx. dimensions (L x W x H)17.7 x 9.4 x 14.9 in
Noise (lower limit)47 dBA
THD< 2.5%
EmissionsCARB, EPA
SecurityLow oil and overload protection
Spark arrestorYes
NeutralFloating
Accessories includedNo
Warranty3 years

Unlike many websites, we did our best to research each of the specs above. That being said, we are not immune to making the occasional mistake or omission. Should you notice any missing or incorrect values, don't hesitate to suggest improvements so we can address the issue.

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About Yamaha

With a rich history of over 130 years, the Japanese based Yamaha Corporation, founded in 1887, has tipped its fingers in every industry imaginable, most notably motorcycles, musical instruments and electronics. The company boasts with a wide range of products, including many of the top rated portable generators. However, it has been reported that many of the newer models are made in China, rather than Japan.

Warranty Information

The Yamaha EF1000iS is covered under a warranty for up to 3 years. This warranty may be limited and may not cover all parts of the generator.
For more information about the warranty of Yamaha generators, please consult Yamaha's warranty policies (opens in a new tab). Alternatively, you can also contact their Customer Support: 1-800-962-7926.

Questions & Answers

What can it power?
Examples of items that can be simultaneously powered.
The examples below are based on a maximum load of 80% and estimated wattages. For a more accurate estimation, use our generator size calculator.
ItemRunning WattsStarting Watts
At homeRice cooker650650
Set of 5 LED light bulbs5555
Total705 W705 W
For campingRV refrigerator180600
DVD player350350
Pair of small speakers4545
Total575 W995 W
For workPaint sprayer600600
Bug zapper8080
Total680 W680 W

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