Well I just added a new one to the household. Because it has no fuel pump and gravity feed, it has ALWAYS started on the first pull. That's great -BUT- the way it responds to half or full power electrical loads is very disappointing, compared to my EF1000iS or the way it SHOULD respond. It may be because it does not seem to have the dual offset alternator windings like the EF1000iS. I used a small 1600W portable heater that has an 800W low setting and a circular saw to perform the electrical load tests. Also, the 20" box fan's airflow cooling me slows noticeably when the heater or saw is turned on. Heater flipped on to high (1,600W) it takes about 3 seconds for the voltage drop to recover. That means a TV or computer would go to "center white dot" when something like a refrigerator or freezer compressor starts, especially from Eco Idle speeds. The Kill-A-Watt shows an AC voltage drop to as low as 80V before it ramps up the RPM's and reads 118V. Resetting the slightly off throttle butterfly to the fully open stop made no diff. It is prolly why the EF2000iS looses to the red box Honda 2000W inverter in starting load tests that I read about. I considered the Honda, but it's bigger engine was thirstier and it had a shorter run time for an equal amount of fuel. The criticized common fuel-ignition knob wasn't an issue to for me to separate the functions, an added rocker switch would fix it. Plus I really like my EF1000iS and the Honda is like $200 more.
Valve Adjustment. A lot easier than the carb and difficult cooling shroud removal required for the EF1000iS! On the EF2000iS, after the 2 screw big blue side panel removal it's just the 4 valve cover bolts, a steel retainer clip removal and it's all apart. I eventually found a good TDC with the eraser end of a long pencil inserted thru the sparkplug hole to follow the piston's position as I very very slowly pulled the recoil starter. After 3 phone calls to my local Yamaha dealer service dept I finally got the specs;
(EF1000iS is .10mm for In & Ex)
After several generator runtimes in 90+ degrees F totaling about 2 hours I measured the actual cold engine valve clearances at:
In: .19mm, Ex: .20mm.
Adjusting the intake, I found the adjuster locknut extremely overtightened. Almost bent the rockerarm loosening it! To simplify the adjusting, use very light finger pressure on the pushrod end of the rockerarm being adjusted to zero out any additional play while you fiddle with the feeler gauge.
After putting it back together it seems to run quieter. At least now I know it has the proper settings. Have not yet tried powering the small chest freezer in the basement and the kitchen refrigerator yet. Shouldn't be a problem as the EF1000iS did it, but with a super rev-n-roar startup!
Re: EF2000iS experiences and the valve adjustment (EF1000iS valve adjustment)
I'm interested in checking the valve clearances for my 1000is and I found your post about the .10mm valve clearances for the 1000is. Also, you mentioned that there is difficult cooling shroud removal.
You also mentioned the carb. Did you mean one must remove that as well?
Do you have any advice for a first-timer in doing the work of checking the clearances? Do you have any pictures or know of any video that is applicable/helpful for doing the 1000is?
Also, while I have it apart, should I be checking for anything else? I haven't decarbonized the cylinder head yet either, though I plan to start using seafoam (or MMO?) in one tank of gas every 100 hours.
The engine has about 1050 hours on it. It's starting to run rough from time to time, though that could be due to the spark plug as it is significantly worn from all the cleaning. I have done the standard 100-hour maintenance ever 100 hours +/- 10 hours.
I use this generator for my main power source for my home so I need it to continue running indefinitely at a minimum of cost, but I can put in all the labor.
If there is any other helpful information or necessary modification please don't hesitate to mention it.