Yamaha EF1000iS Inverter Portable Generator Review

Yamaha EF1000iS inverter Generator

Yamaha EF1000iS Generator

For a high quality electrical output under 1000 watts in a portable generator the Yamaha EF1000iS is an excellent choice.

Yamaha is world renowned for their motor cycles, ATVs, watercraft, marine engines as well as power equipment which includes generators and inverter generators.

They are known for the reliability, efficiency and durability of their products. With the inverter generators they use the latest technology combined with their reliable and fuel efficient engines to give you a product that is at the top of the line.

The EF1000iS inverter generator is one of the generators that they produce. It is small, lightweight and compact.

It is able to deliver up to 1000 watts of clean electrical power with unmatched fuel efficiency and is ideal for those applications where you do not require too much electrical power.

Power Output and Generation

The Yamaha EF1000iS inverter generator is equipped with a 50 cc OHV single cylinder air cooled engine which lets it deliver 900 watts of continuous power while being able to surge up to 1000 watts.

Outlet Configuration:

Power output is through either the AC circuit or the DC circuit. The DC circuit is 12V at 8 amps providing up to 96 watts of charging or DC equipment power. The AC circuit provides output through the two 5-15R outlets for a total available output of 7.5 amps at the full 900 watts.

This makes it a good unit for powering low amperage equipment like a couple of lights, radio, or small power tool. It is not intended for large continuous load, but the inverter gives quality power for electronics.

Fuel Type and Noise Levels:

The Yamaha EF1000iS inverter generator uses gasoline as its fuel. It has a fuel tank capacity of 0.66 gallons and can run for almost 12 hours on one tank of gas at 25% load capacity. It does not have a fuel gauge.

This generator is very quiet producing between 47dB and 57dB of sound when running at 25% load capacity at 7 meters. With some increase in noise levels at higher loads, but still well below the typical open systems without insulated enclosures.

This is due to excellent design which takes the small size engine, encases it in a well-insulated cover that reduces engine mechanical noise to bare minimum and then providing a good muffler/spark arrestor to take care of the exhaust noise.

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Video Review Summary:

Dimensions and Weight

The Yamaha EF1000iS inverter generator is extremely compact and light. Its overall dimensions are 17.7 x 9.4 x 14.9 inches ( L x W x H ) making it easy to store just about anywhere.

It weighs in at 27.9 lbs. and with a tank of gas is only 32 lbs. dripping wet. Thus making it ultimately mobile.

Typical Uses and Needs

The EF1000iS is a light weight and compact portable inverter generator supplying up to 900 watts of continuous clean electrical power. It can run for almost 12 hours on 5/8 gallons of fuel at one quarter load capacity. Even at half to ¾ load you’re going to get a day’s work out of it.

This makes this generator ideal for those applications where you require limited wattage. It is ideal for camping, tailgating, for use in your RV to run a few electrical appliances. It can also be used as a backup power source in your home to run an absolute essential appliance in a pinch.

Being able to supply you with clean electrical power means you can run your sensitive electronic equipment safely while using this generator.

Display & Control Panel, Start-up

The control panel of the Yamaha EF1000iS inverter generator is very simple and easy to understand.

It is located on the side of the generator and when you face it you will find at the top left 3 indicator lights. The one to the extreme left is the Overload indicator light, the one in the center is the AC pilot light and the one to the right is the Oil warning light.

To the right of these lights you have the Choke knob and next to it you have the Fuel Cock Knob. Below the indicator lights you have two 15 amp 120Volt AC receptacles and to the right of these receptacles you have the Engine switch.

To the right of the engine switch you have the Ground terminal. Below the 120Volt receptacles you have the 12 Volt 8 amp DC receptacle and next to it to the right you have the DC circuit protector. To the right of this you have the Economy control switch to help extend the fuel usage.

What this smaller model does not have are hour or voltage meters on the control panel.

Start up

Yamaha EF1000iS inverter generator is equipped with a recoil starter to start the engine. Before you start the generator check the fuel level and the engine oil level. Make sure that there are no loads connected to the generator. Turn the Economy control switch to the Off position.

Here are the steps to be taken to start the generator.

  1. Open the fuel tank air vent by turning the air vent knob 1 turn counter clockwise while holding the fuel cap.
  2. Turn the Fuel cock knob to the On position.
  3. Turn the Engine switch to the On position.
  4. Pull the Choke knob fully out.
  5. Pull slowly on the recoil starter till you feel a resistance then pull sharply.
  6. After the engine starts let it warm up till you can push the Choke knob to its original position.

Shut Down

  1. Turn Off all electrical devices.
  2. Turn the Economy control switch to the Off position.
  3. Disconnect all electrical devices.
  4. Turn the Engine switch to the Off position.
  5. Turn the Fuel cock knob to the Off position.
  6. Turn the Fuel tank air vent knob clockwise till it is finger tight.

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Here are some of the features of the Yamaha EF1000iS inverter generator.

  1. It is very compact and lightweight, weighing in at only 27.9 lbs. and 32 lbs. with gas which makes it very portable.
  2. It has a smart throttle with load sensing RPM control which gives it greater fuel efficiency and reduces the noise by adjusting the engine speed to match the load.
  3. It has an auto warm up which automatically increases the engine speed for 4 to 6 minutes during cold startups.
  4. It has two 120 Volt AC receptacles and one 12 Volt DC receptacle and it comes with cables to charge batteries.
  5. It has a dual coil alternator stator which allows it to give out a greater output at lower speeds which saves fuel while lowering the noise level and increasing the engine life.
  6. It has a centralized control panel for easy access.
  7. It has a 50 cc OHV with improved efficiency, low oil consumption and increased reliability.
  8. It is one of the quietest generators in its class producing between 47dBand 57dB of noise at 25% load capacity.
  9. It is CARB compliant and available in all 50 states.
  10. It comes with a 3 year factory warranty which covers all parts and workmanship.

Care and Maintenance and Use

Proper care and maintenance is required to keep your Yamaha EF1000iS generator to run at its best and perform safely. Here is the maintenance schedule as recommended by Yamaha for this generator.

Pre operation check

  1. Check exhaust system for leakages, tighten or replace gasket if necessary.
  2. Check the engine oil level.
  3. Check fuel hose for cracks or damage. Replace if necessary.
  4. Check the Choke operation.
  5. Check the recoil starter operation.
  6. Check to see if the AC pilot light comes on.

First month or after 20 hours

  1. Change the engine oil.

Every 3 months or after 50 hours

  1. Check the spark plug, clean and adjust gap as necessary.
  2. Clean the air filter. Replace if necessary.

Every 6 months or after 100 hours

  1. Change the engine oil.
  2. Clean the fuel tank filter. Replace if necessary.
  3. Check all fittings and fasteners and correct as necessary.

Every 12 months or after 300 hours

  1. Check and adjust valve clearances.
  2. Check the breather hose for cracks or damage. Replace if necessary.
  3. Check the muffler screen and spark arrester. Clean or replace if necessary.
  4. Check the cooling system and fan for damage.
  5. Decarbonize if necessary.

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Warranty and Repairs

Yamaha - 3 Year Limited WarrantyThe Yamaha EF1000iS inverter generator carries a factory warranty which covers the whole generator for parts and workmanship for a period of 3 years if used for non-commercial purposes. If used for commercial purposes the warranty is valid for 2 years.

The generator needs to be registered for the warranty to be in effect. The warranty is transferable as long as the generator is inspected by an authorized Yamaha dealer or service agent. All transportation costs are to be borne by the customer.

Consumer Comments

The Yamaha EF1000iS inverter generator scores over 90% of rating above 4 stars on Amazon. The customers who bought this generator were very happy with its performance.

Most of them commented on the fact that it was very lightweight and compact and very easy to take it wherever they wanted.

They also commented on the fact that it was very quiet as compared to other generators of similar size. Most of them also liked the fact that it is very fuel efficient and that it ran all day on less than 1 gallon of gasoline.

They also liked the fact that it supplied clean electricity which is safe for sensitive electronic equipment.

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Pros & Cons


  • It is very lightweight and easily portable.
  • It is very quiet.
  • It is very fuel efficient with almost 12 hours of run time at 25% load capacity.
  • It has a smart throttle that adjusts the engine speed to the load.
  • It supplies inverter “clean” output for use with sensitive electronic equipment.
  • It is CARB compliant for use in California.
  • It has one of the best warranties available for portable generators at 3 years covering  all parts and defects in workmanship.
  • It has 7.5 amps of AC output with the 5-15 receptacles making standard extension cords usable for a number of applications.
  • The 12 Volt DC output with cables is handy for battery charging and powering small electronics.


  • It can only supply 900 watts of continuous power, although this was the intended purpose.
  • Has limited applications due to low wattage produced. Again part of the intended design.


The Yamaha EF1000iS inverter generator is available in online stores. It is available at Amazon and other outlets for under $800.00 with free shipping. Check out the latest price deal here:

Yamaha EF1000iS 1,000 Watt 50cc OHV 4-Stroke Gas Powered Portable Inverter Generator (CARB Compliant)


When you get a Yamaha EF1000iS inverter generator you may want to get a few accessories for your generator.

You can find a generator cover that will help you keep your generator free from dust and the elements when not in use.

Yamaha ACC-GNCVR-10-01 Generator Cover for Models EF1000iS

Also available is a funnel with a flexible spout to help you fill the engine oil.

TEKTON 6094 2-In-1 Funnel with Flex Extension 40 oz.

There are various sizes of power cords available to help you run your various appliances.

To ensure that you don’t try to overload the generator you may also want to pick up a AM/Watt Appliance Load Tester.

Reliance Controls THP103 AmWatt Generator Appliance Wattage/Amps Load Tester

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The Yamaha EF1000iS inverter generator is a very compact and lightweight and extremely portable generator.

Since it can only produce 900 watts of continuous power it is ideal for applications that do not require too much power. It is very quiet and fuel efficient making it an ideal companion to take camping or for tailgating parties.

Since it provides clean electricity it can be safely used with sensitive electronic equipment. It can be used to power the lower wattage needs of essential appliances at home during power outages.

The construction is high quality and due to its insulation and compact design as well as the warranty you will pay a premium for the machine. This is typical of the better machines and service you’ll find in the high quality category.

Similar Generation Units:

The following Yamaha Inverter Generators are also available at different wattage sizes:

Yamaha EF2000iS 2,000 Watt 79cc OHV 4-Stroke Gas Powered Portable Inverter Generator, CARB Compliant, Blue

See: Full Review EF2000iS

Yamaha EF2400iSHC Portable Generator

See Full review EF2400iSHC

Yamaha EF3000iSEB Portable Generator

See 3000iSEB Reveiw here

Yamaha EF4500iSE 4,500 Watt 357cc OHV 4-Stroke Gas Powered Portable Inverter Generator With Electric Start (CARB Compliant)

Yamaha EF6300iSDE 6,300 Watt 357cc OHV 4-Stroke Gas Powered Portable Inverter Generator With Electric Start (CARB Compliant)

Go Here for the Full Review of the EF6300iSDE

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