​Yamaha EF1000iS Review

Last updated September, 2023



Yamaha EF1000iS review





​Weighing in at less than 30 pounds, the Yamaha EF1000iS is an ultra-portable power solution that powers anything in its capacity for a good 12 hours on a full tank. 

It features a simple design with clean easy filling, a decent power output at 900 Watts and the ability to filter out noise through the sound reduction system. 

This is an intelligent unit that is capable of sensing changes in load and accordingly adjusting the fuel throttle. It is CARB compliant and comes with a two-year consumer warranty.

​About the ​​​​​​Yamaha EF1000iS

First off, the Yamaha EF1000iS isn’t your powerful compact generator, it is more of a temporary solution or a portable answer to specific needs. Do not expect to operate your entire range of machinery from the power generated by this generator. To start with, it has got a nominal output of just 1000 Watts, which is actually a sober 900 watts enough to power a single heavy machinery. It is built using an inverter system that helps generate more power from less fuel and produces perfect sine waves that are more reliable and dependable. As for usability, it works great in power outages keeping a large refrigerator powered up plus a few fans and couple of CFL bulbs. Just don’t try to overload this little beauty, it can trip and needs a manual restart.

The low power output and use of sound reduction technology together actually help drop noise levels by a good 10 dBA over its elder 2000 Watt rated sibling. This particular generator uses noise absorbing glass wool construction that dampens noise levels and helps keep it at a minimal sound level. Add to this its minimal weight of around 27.6 pounds and you get a lightweight generator that is going to pass any nature trail requirement. I have taken this along on camping trips that stretch over a week and powered my cell phone, laptop, a 2.1 speaker system and had juice leftover for the night to keep two table fans running on full blast throughout the night. The 12-hour battery backup, officially suggested by Yamaha actually applies to full load and not partial output. The
Yamaha EF1000iS can actually recharge a few batteries for you with the 12 Volt DC outlets, which is an excellent addition for boat owners, auto or RV enthusiasts.

On a final note, the Yamaha EF1000iS offers exceptional fuel efficiency and a decent warranty cover, with the dependable name of Yamaha. One thing is for sure, the engine on this inverter generator is not going to fail you within a couple of years and if it does, the warranty covers replacements and repairs free of cost.

Yamaha EF1000iS


  • ​Quite operation that cuts back on gas and fumes, can operate throughout the day on a full tank and low load, exceptional engine quality and decent efficiency. Small and compact.


  • ​Won’t power everything in your RV or home so don’t try to overload it as it will trip continuously. Also, tends to maintain a medium setting by default so expect a sudden surge when you connect an additional load to it. Expensive considering its limited 1000 Watt maximum rating.


  • ​Maximum output is 1000 Watt but continuous load is rated at 900 Watt.
  • ​Ultra low below 50dBA noise levels thanks to the sound reduction system.
  • Lightning Bolt
    ​Variable engine speed based on the total load.
  • Lightning Bolt
    ​Operates for 12 hours on a single refuel of the 0.66 gallon tank.
  • Lightning Bolt
    ​CARB compliant.


Running watts 900
Starting watts 1,000, 8.33 Amp
Engine HP/cc 50cc OHV 4-stroke Engine
Starting method Recoil Start
Low oil shutdown YES
Fuel tank size (gallons) 0.66 Gallon
Run time at 50% Load 18 Hours
Outlets 2 x 12Amp/120V AC, 1 x 12 Volt 8A DC
Handle style Top Folding
Wheel type No Wheels
Warranty 2 Years
Yamaha EF1000iS review
Yamaha EF1000iS
The smallest dependable portable generator, Yamaha EF1000iS with its 50cc OHVC engine delivers an impressive 8.3 Amp or 1000 Watt starting wattage that helps power a few important RV or boat equipment, charge batteries and keep your camping trip lighted up. It is a compact power solution for tiny power needs.
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