Yamaha Inverter Generator Issues

Wondering if any CMRA peeps have seen this issue:

I have a 2.5 year old Yamaha EF2000IS inverter generator - bought it new, always ran it with gas tap off till it ran out of gas to prevent chances of carb issues. Recently, under load it started having issues where it would almost die, then rev up again, work for about 20-60 seconds, almost die then rev up again. The gap between the issue is consistent - eg it's either every 60 seconds or every 20 seconds depending on how many warmers I'm running (so relates to load). Generator runs perfect when under no load. It does this on both eco mode and non-eco mode but with a different gap in between the issue occuring. This appears to be an electrical issue in however the inverter senses how much load it is under, or manages it's output. I have tried this with different sets of warmers incase I had some kind of intermittent short - no issues - has never tripped the breaker.

I took the carb out to look at the jets - it was as clean as the day it was new - took out the jets and blew air/carb clean through them anyway. Float valve works as expected - I haven't taken it out and cleaned it tho and haven't changed the floatt level. The carb is pretty straightforward. I looked at the spark plug - it's a little on the lighter side, so might be running a tad weak, but I don't think it's related. I read this is normal online.

I cleaned out the tank, fuel filter area, went and got fresh gas. No dirt, clogs etc.

Same issue after all this work, so didn't change behavior a bit.

Probably need to take it to a small engine specialist, unless anyone on here has had this exact issue before, and it wasn't a dirty carb. I found one reference to a governor online, but with no details and seems really uncommon. Also couldn't find any common replacement parts on eBay suggesting this is rare.

Anyone had this, or have a recommendation on someone good with generators? The thing was 800 bucks new, and I got 2.5 years out of it, so it's right on the edge of having paid for itself, maybe.

I can't help...other than to highly recommend the 3500w model from harbor freight. Love mine.
-Cody

Sounds like my Honda generator. Took the carb apart and used carb/contact cleaner everywhere. Works fine now. I’d take the carb back apart /remove the float needle and clean everything out.

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Originally Posted by Carl Price

Sounds like my Honda generator. Took the carb apart and used carb/contact cleaner everywhere. Works fine now. I’d take the carb back apart /remove the float needle and clean everything out.

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Doing that right now. Float is plastic and non adjustable. Putting is back together now.


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Cleaned out float valve. Everything looks spotless. Float valve is not adjustable. Works as you would expect blowing through the inlet pipe and moving the float up and down.

Thought we had victory when starting it up and putting the warmers on - took 4 minutes to happen the first time, then happened inconsistently every 30 seconds to 2 minutes. Not sure if any improvement - seems about the same. Tried to induce it by varying the load by plugging in/unplugging warmers. Couldn't induce it. Also only does it when warm.

Troubleshot the idea that the float was low ie fuel starvation - there is definitely no cloggages in the tank, filter, pipe etc...the flow could run a V8. I turned off the fuel tap and thought this might induce it - ie if the float level is low, turning off the fuel tap would make it happen pretty quickly and consistently, ie within 1 minute (normally it takes about 4 minutes for the carb to empty and run out of fuel). It did not do it when running out of fuel (until it actually ran out of fuel).

When it happens, it is like the spark is cut for about 4 seconds, then starts firing again just as it is about to die - https://www.youtube.com/watch?v=SCC6iW6LktU

Just as I wrote this up, I noticed on the video that the oil light comes on just when it happens...that might be the issue - it's a bit too late to be firing up the generator in the street to test this out. I'll try it later in the week when I'm back home. It certainly would explain why it happens when it's warm also I think. I did give it an oil change a few months ago and it only started happening since that - I would think it's just an oil level, however, that would make you think it would happen when cold. If it's an oil pressure sensor, the oil may not be holding pressure when it's hot - I'll dump out whatever is in there and go from there. I can't remember what I put in for grade.

May as well post up here, so someone in the future can find this post on t'internet...

I had a similar issue with the same gen. It was slightly low on oil. Add a few ounces and see if the issue goes away.

I can't remember what they call this but it is a known issue.
Let me see if I can find the youtube video on it. Basically needs a carb cleaning is all.

It looks like it is an oil issue judging by the light coming on when it dies. I haven’t verified this for sure yet tho.

In the sun at the track I’ve never been able to see the oil light come on when it’s been misbehaving. Much like you don’t see if you warmers are on or off in the sunlight. ;)


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I have the same generator and this is the exact behavior mine exhibits when it first gets low on oil. Like you mentioned, in the sun it is almost impossible to see the low oil light.

I forgot all these generators have that protection circuit that. It kills it when oil is low.

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Originally Posted by Rab McNaught

Cleaned out float valve. Everything looks spotless. Float valve is not adjustable. Works as you would expect blowing through the inlet pipe and moving the float up and down.

Thought we had victory when starting it up and putting the warmers on - took 4 minutes to happen the first time, then happened inconsistently every 30 seconds to 2 minutes. Not sure if any improvement - seems about the same. Tried to induce it by varying the load by plugging in/unplugging warmers. Couldn't induce it. Also only does it when warm.

Troubleshot the idea that the float was low ie fuel starvation - there is definitely no cloggages in the tank, filter, pipe etc...the flow could run a V8. I turned off the fuel tap and thought this might induce it - ie if the float level is low, turning off the fuel tap would make it happen pretty quickly and consistently, ie within 1 minute (normally it takes about 4 minutes for the carb to empty and run out of fuel). It did not do it when running out of fuel (until it actually ran out of fuel).

When it happens, it is like the spark is cut for about 4 seconds, then starts firing again just as it is about to die - https://www.youtube.com/watch?v=SCC6iW6LktU

Just as I wrote this up, I noticed on the video that the oil light comes on just when it happens...that might be the issue - it's a bit too late to be firing up the generator in the street to test this out. I'll try it later in the week when I'm back home. It certainly would explain why it happens when it's warm also I think. I did give it an oil change a few months ago and it only started happening since that - I would think it's just an oil level, however, that would make you think it would happen when cold. If it's an oil pressure sensor, the oil may not be holding pressure when it's hot - I'll dump out whatever is in there and go from there. I can't remember what I put in for grade.

May as well post up here, so someone in the future can find this post on t'internet...

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I have one apart with the same issue. did'nt think about low oil :deadhorse:

The CMRA has 6 Yamaha generators of various sizes. They all have low oil protection circuits. Go ahead and change the oil while you are at it. I slightly overfill ours just to be safe.

This was the oil circuit cutting the power out when it was warm and under specific load. Like Walter suggested I gave it an oil change and filled it a couple of mm above the recommended level. All good now.




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Originally Posted by Rab McNaught

This was the oil circuit cutting the power out when it was warm and under specific load. Like Walter suggested I gave it an oil change and filled it a couple of mm above the recommended level. All good now.




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Great news. now how much oil does the 2000 series hold??

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Originally Posted by Dewayne Davis

Great news. now how much oil does the 2000 series hold??

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A tiny amount. 400ml, but I'm not even sure it took that much. It certainly didn't have 400ml in it when it had the issue...oops.