# Yamaha EF 2000 Generator- valve clearance



## bigbuilder (Aug 2, 2020)

Hello everyone,

Thank you very much for letting my join your community.

We have an old yamaha ef 2000 generator. Not the inverter type.

We have been using it alot and ran into a non running issue. I tore it apart and found more carbon buildup than I have ever seen.

We have not been able to find any info on this thing. We cleaned it all up. Lapped the valves and want to put it together but cannot find any info. Nothing. Not even the yamaha dealer.

The is a side valve type engine. We will need to grind the valves to adjust the clearance.

If anyone can find a manual or help us with the clearance specs I would greatly appreciate it.


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## iowagold (Jan 22, 2020)

snap a picture of the generator and the generator tag.


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## bigbuilder (Aug 2, 2020)

Hi, Thank you for the reply. This is the only two pictures I took. I can take more tomorrow when I get back to the shop.


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## iowagold (Jan 22, 2020)

ahh flat head
HOW TO FIX The Valve Clearance On A 4 Cycle Flat Head Engine
intake .008 inches intake and .012 inches exhaust or 8 thou and 12 thou
or if you are metric only in your shop
.203 mm intake and .305mm exhaust
that should get you super close!
if you just did a valve job i would say a bit wider is ok
or check the clearance after running the engine for 50 hours after the new valve job.
and that is for a cool engine on those numbers.

i guess i would to have swapped the generator head to a late model ohv before rebuilding a flat head..
the ohv is way quieter at least by 10db and uses less fuel per hour (almost 1/3 better on the fuel)


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## bigbuilder (Aug 2, 2020)

Hi, Thank you very much. Yes it is loud and it is old. But it was doing the job for us.

Its really funny how little information there is on these generators.


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## iowagold (Jan 22, 2020)

yup the old pre internet stuff there is not docs in digital form unless some one has a club to rebuild them.
B&S has several clubs for the old stuff.. as well as maytag etc.
think the old antique engine clubs like the old threshers bunch here in Iowa..
lots of good info in those clubs!

lol on the loud!
i get a kick out of every one here where i love during an outage..
the old flat heads sound like some one passing gas on a sports events bleacher! 
lol!!
loud and nasty!!
grin!!

yea the late model inverter units are super quiet..
and the cool thing is they can be ran in parallel with another same model for more power as expansion!

the late model of the larger honda eu7000is is fuel injected!
yup it has a computer to adjust the air fuel ratio.
so it is always perfect run like on you late model cars and trucks.
and it adjusts for when you are in the mountains as well.
we will see more fuel injected units in the next few years on the gen sets.
the tech is getting cheaper by the day.

if you have a db meter app on the smart phone
let us know how loud it is!

I have my gear here down to 52 db with out a silent box.
if you did not see the lights on at the house you would not know I had power quiet.


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## bigbuilder (Aug 2, 2020)

Hi, Well i got it all back together and running well it seems. Not sure but the muffler seems to be hotter than it it should be? is that possible?


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## tabora (Sep 6, 2018)

bigbuilder said:


> Hi, Well i got it all back together and running well it seems. Not sure but the muffler seems to be hotter than it it should be? is that possible?


If it's glowing red, then it might be a tad hot... 😈 Double check your valve clearance and also make sure it's not running too lean; that makes for a hot muffler!


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## bigbuilder (Aug 2, 2020)

Ok. I will double check that. There was no clearance before. I was diligent to grind to 8 thou and 12 thou today when we put it back together.


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## iowagold (Jan 22, 2020)

are you ethanol gas?


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## bigbuilder (Aug 2, 2020)

Yes. We run gas with enthanol in everything unfortunately.


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## iowagold (Jan 22, 2020)

yea ethanol fuel it has more o2 in the burn.
hotter burning..
the carb needs to be a bit richer if you are over the e10...
there is e15 now in some areas...
if you can get strait gasoline try that to prove the point..
you might have to get 93 octane or higher to get the ethanol free. 
but worth it for testing..

the guys are fighting this on the chain saws as well...
ethanol will kill a good older stihl chain saw... even with the good synthetic mix oil...
it just runs too lean.

the new honda eu7000is cures the ethanol issue with full blown fuel injection.
just like a late model car.
and it runs better for epa too.


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