ef3000iSEB: fluctuating engine speed in economy mode w/no load

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ef3000iSEB: fluctuating engine speed in economy mode w/no load

MXTex
Greetings.  When in economy mode, w/no load, my ef3000iSEB fluctuates engine rpm.  Revs up, then slows down, revs up, slows down, up, down, up, down.  If I put a load on it, in economy mode, it'll even out..most of the time but will still fall into the surging sometimes with a load.  I've disassembled and cleaned the carb thoroughly; ensuring all jets and passages were clean and clear.  This had no effect.  I'm currently adjusting the valves, which appear to be on the loose side, and have a throttle control motor on order.  When the genset is in normal mode (economy off), it revs up nicely and holds a steady rpm.  If any of you have had this issue and can short cut my troubleshooting, I'd appreciate some guidance.  
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Re: ef3000iSEB: fluctuating engine speed in economy mode w/no load

YamahaGenuineParts.com
Administrator
I would revisit the carb clean and make sure main jet and pilot jet are removed for cleaning, along with the main nozzle and placed in a small container and left in combustion chamber cleaner overnite, after which they should be blown out with compressed air and held up to the light to ensure they are clear through, carb body should also be sprayed up liberally with combustion chamber cleaner and left overnite before blowing out and reassembly.Another thing you may wish to check for is any intake leaks. when your generator is idling try spraying the carb intake area with WD40 and see if there is any change in the idle speed, this would indicate an intake leak.
Good luck.
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Re: ef3000iSEB: fluctuating engine speed in economy mode w/no load

MXTex
Update.  I disassembled the carb...again and cleaned thoroughly.  Main and pilot jets were removed and cleaned with carb cleaner and verified to be clear.  I also adjusted the valves, (which were loose), installed a new properly gapped plug, a new throttle control motor, filter and fresh fuel.  It still fluctuates engine speed, and does so in both non-economy and economy modes.  You can watch the throttle control motor moving back and forth so what ever the root cause, it's manifesting at the throttle control motor.  In following the service manual troubleshooting flow diagram, my next step is to check the valve face and seats.  I've got the cylinder head removed and valves pulled out.  Although the exhaust side is fairly carboned up, nothing looks too bad.  I'll be measuring everything closely against spec with my verier calipers.  Any feedback would be appreciated.  The last step in this troubleshooting process is replacement of the control board, which is in the neighborhood of $700!!!  I don't want to do that.  
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Re: ef3000iSEB: fluctuating engine speed in economy mode w/no load

MXTex
Well, I got tired of looking at all the parts laying all over the place so reassembled the generator for fear of forgetting how she goes back together.  I didn't find anything definitively wrong although as stated before, the exhaust port of the cylinder head was quite carboned up.  At one point in this generators life, the spark arrestor in the muffler completely clogged; shutting the motor down.  So maybe all the carbon build up being cleaned up will resolve the issue.  Additionally, I heard from one owner who had the exact same issue.  A dealership resolved his and said the cause was a loose rocker arm stud.  So while I had the head removed, I pulled the rocker arm studs and reinstalled with red loktite; then readjusted the valves again.  

Keeping my fingers crossed that this gets it.  If anyone has any additional feedback, I'd appreciate hearing.
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Re: ef3000iSEB: fluctuating engine speed in economy mode w/no load

MXTex
Well, it didn't work. ugh  It does the exact same thing.  I've followed the service manual troubleshooting sequence step by step and there's only one item left.....faulty controller.  Problem, the controller costs $700.  

Anybody know if I can get this controller repaired?
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Re: ef3000iSEB: fluctuating engine speed in economy mode w/no load

brucenprentice
Try turning up the idle speed a touch. Will have to break plastic cap to gain entry.     B
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Re: ef3000iSEB: fluctuating engine speed in economy mode w/no load

MXTex
Thanks for the feedback Bruce.  For now, I'm headed down the controller route.  Everything from the service manual troubleshooting flow chart is pointing to the controller.  The problem is a controller is very expensive.  Fortunately, I've found a controller repair facility that is reasonably confident they can repair, at a fraction of the cost of a new one. (< $100)  They should receive it tomorrow so we'll see.

A little back ground, I bought this generator from a friend of mine for $250.  It wasn't running.  Mitch Williams pointed me in the direction of the spark arrestor and sure enough, this is what was preventing the motor from running.  But once running, this throttle hunting issue manifested.  It was a pre-existing condition of the generator prior to the spark arrestor clogging so I knew about it prior to purchase and thought I could resolve easily.  Boy was I mistaken.  Anyway, hopefully the controller will be repairable and I'll wind up with a nice running generator on the cheap.  But if the controller can't be fixed, I'm not sure the generator is worth enough to buy a $700+ part.  We'll see.

You'd be surprised how many email inquiries I've received from folks experiencing this exact same issue with this model generator.  I really hope to be able to report that the controller repair is the solution.  More later.
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Re: ef3000iSEB: fluctuating engine speed in economy mode w/no load

brucenprentice
 Let me know if the controller (board) repair works. My information suggests their has been a problem in this area for sometime. Yamaha of america techs when contacted (must be authorized dealer) recomend changing the speed control board with very little discussion. Been told new board is of a different design. Please be advised that this all second hand information. After much ado my ef3000iSEB seems to run just fine, however econ rpm seems higher than I remember.  Good Luck.       B
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Re: ef3000iSEB: fluctuating engine speed in economy mode w/no load

MXTex
Thanks Bruce.  If the controller checks out ok, then I'll replace the speed limiter as you suggest.  Perhaps YamahaGenuineParts has a contact within Yamaha to check on this issue.
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Re: ef3000iSEB: fluctuating engine speed in economy mode w/no load

MXTex
Well, I got a call from my controller repairman yesterday to be informed that they can't help me.  arghhh.  Speedy and I exchanged emails and he's going to see if he has contacts within Yamaha that can assist.  This thing is really starting to frustrate me.  There's got to be something better than a $700+ solution.  
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Re: ef3000iSEB: fluctuating engine speed in economy mode w/no load

brucenprentice
Idea: Case of beer, few sticks of dynamite, couple good friends: Have a pre-super bowl generator disposal party.   Good luck.       B
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Re: ef3000iSEB: fluctuating engine speed in economy mode w/no load

YamahaGenuineParts.com
Administrator
In reply to this post by MXTex
Hello guys, sorry I was away for a while there.
If you are still experiencing problems with your generator , I would strongly suggest taking it to a Yamaha Generator dealer who services them on a regular basis as it is pretty difficult to diagnose over the internet or telephone. I would not guess at the cause, by simply throwing parts at it, this will get expensive as you have mentioned earlier. Yamaha warranty is 2years from purchase.
Regards  
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Re: ef3000iSEB: fluctuating engine speed in economy mode w/no load

MXTex
In reply to this post by brucenprentice
Well, it's fixed.  And thank goodness I didn't spend any money on a non-returnable, expensive, electronic control unit.  I went back into the carburetor for a 3rd time.  This time I borrowed my wife's granny glasses and made a very close inspection of the pilot jet and found it to be clogged.  Carb cleaner and compressed air would not clear it so I used a needle to very gently push the blockage out.  Reassembled and it now runs normal.  Thank goodness.  I had cleaned the pilot jet two other times during carb disassembly but missed the most important port right on the tip.  This jet is not similar to others I've seen in that it had two ports on the side which were clear.  I thought these somehow provided the fuel.  But there's another very, very small hole in the jet tip that was clogged.  It's so small, you can barely see it with the naked eye when cleared.  Anyway, it's clear now and we're back in business.  
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Re: ef3000iSEB: fluctuating engine speed in economy mode w/no load

YamahaGenuineParts.com
Administrator
Hey, Hey glad to hear it ....the mystery is now solved, well done, I am sure others will be having a second look at there carbs for sure.
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Re: ef3000iSEB: fluctuating engine speed in economy mode w/no load

StevenWells
I have the EF2400is.  After running the generator on my travel trailer for fourteen hours, I noticed the engine rev up well above normal when I removed the load before refueling.  The engine also ran too fast after I re-started it, but when I re-applied the load it seemed to run fine.  I again noticed this during the next two refuelings.  Approximately 20 hours after I first noticed the erratic behavior, the engine began changing speed under load, mostly faster than normal, sometimes slower than normal.  This caused the generator to go into overload and the engine ran very fast in this overload condition.  Past experience has shown that the engine should run at idle when in overload.  Now the generator mostly runs way too fast under no load and sometimes runs too slow and does not produce the correct power.  The AC power indicator light flashes on periodically but mostly says off.  
I've cleaned the carb jets, spark plug, and spark arrestor.  there were no signs of any problems there, although I noticed that the dealer did not replace the bolt in the air cleaner case from previous work.  I had the cylinder head replaced in the spring under warranty because the valves would not stay in adjustment.  I had less than 15 hours on it since the replacement before this weekend.  Any ideas?  I'm guessing it's either the speed limiter assembly or the TCI unit.  Does anyone have any troubleshooting techniques?  Thanks in advance for any help.
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Re: ef3000iSEB: fluctuating engine speed in economy mode w/no load

robertbruce
In reply to this post by YamahaGenuineParts.com
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I agree with this advise, use the warranty...

i've travelled up and down the eastern seaboard often stopping at yamaha dealers looking for litre bottles of yamalube....If you are in Australia, Pittman Yamaha in South Australia is the best ive found...i have no alliegence to them
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Re: ef3000iSEB: fluctuating engine speed in economy mode w/no load

Don Daugherty
In reply to this post by MXTex
I would like to locate this small port at the tip and try to clean mine do you have a picture of where it would be. Mine generator was working fine until I left bad gas in it and now clean enough to run it will not idle up. Thank you for you time