yamaha 1kva generator

Submitted: Friday, Apr 29, 2011 at 11:45
ThreadID: 85948 Views:7502 Replies:13 FollowUps:9
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I am using a yamaha 1kva geneator which is 6 yo. I have had problems for a number of years with the generator surging up and down with no apparent reason. The only thing which seems to remedy the problem for a while is to dismantle the carby and blow it out with a compressor - not always practical in the bush. When I do this there is a small amount of fine dust in the bowl. There are 2 filters between the tank and carby (i have added an extra one) but this hasn't fixed the problem. Am I the only one out there who has this problem?
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Reply By: nick b - Friday, Apr 29, 2011 at 12:02

Friday, Apr 29, 2011 at 12:02
What you could try is empty out tank on to a fine white cloth to see what's in the tank , if it leaves crud or dark stain .
I had this problem ,all the cleaning didn't fix it so replaced tank .
Cheers Nick b

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AnswerID: 452714

Follow Up By: Mezza - Friday, Apr 29, 2011 at 12:17

Friday, Apr 29, 2011 at 12:17
OK I have emptied the tank on a number of occasions and cleaned the filter. I have wondered if dust is drawn in thru the breather on the cap. would have thought that 2 filters would have taken care of this. was your genny a 1kva YAMAHA?
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Follow Up By: Member - nick b - Friday, Apr 29, 2011 at 15:23

Friday, Apr 29, 2011 at 15:23
Gooday Mezza : My problem was on a car & when I emptied out tank on cloth it just left a bark stain but that all it took to block up filter elect pump & carby - very fine crud - to my surprise. also other posts re fuel age etc also what type of fuel.
I think if you could tel us full details i.e is the genny in open, it may need to be covered when travelling . how often is it used .
regards nick
Cheers Nick b

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Follow Up By: Mezza - Saturday, Apr 30, 2011 at 18:37

Saturday, Apr 30, 2011 at 18:37
thanks for the help. The generator has usually been used on the ground and has always travelled in a box inside the car. Just recently I tried placing the genny on a wooden shelf (old drawer) and then on the ground. It ran allright for about a week and then started its shenanigans again hunting up and down. This hunting isn't always consistent, it may behave for say 15 seconds then start hunting up and down again. Thanks, mezza
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Reply By: Member - Keith C (NSW) - Friday, Apr 29, 2011 at 12:36

Friday, Apr 29, 2011 at 12:36
Mezza, have you cleaned the jets in the carby? taken them out and cleaned them?It sounds like there is a partial blockage, probably in the main jet, use fine fuse wire to clean it out, while the carby is off, flush the tank with clean fuel, it doesn't take much crud in the jets to make these small engines hunt.Good luck, Keith
AnswerID: 452718

Reply By: Bushranger1 - Friday, Apr 29, 2011 at 12:41

Friday, Apr 29, 2011 at 12:41
One of the biggest problems with infrequently used outdoor equipment is stale fuel. It will gum everything up quick smart.
Modern fuel goes off much faster than in the past so this is becoming a common cause of problems in small engines.

I started using a product called STABIL about 10 years ago & I have never had an engine fail to start since. It will extend the life of the fuel for up to 2 years but has to be added at the time of fuel purchase. It will not fix fuel that is already gone off. I bought my last bottle at Bursons auto but I believe a similar product is available at marine engine suppliers. It can be used in all 4 & 2 stroke engines.

Wont fix your immediate problem but I bet it stops it happening again.

Cheers
Stu.
AnswerID: 452720

Reply By: Rockape - Friday, Apr 29, 2011 at 12:51

Friday, Apr 29, 2011 at 12:51
Mezza,
two other things that will cause the problem are air leak through a carby gasket and a stretched governor spring.

Hope you find it.
AnswerID: 452722

Reply By: Mezza - Friday, Apr 29, 2011 at 12:52

Friday, Apr 29, 2011 at 12:52
I have cleaned the jets carefully and intend to soak carby in some sort of cleaner as the next step. will also try Stu's suggestion for this fuel additive.
AnswerID: 452723

Follow Up By: Member - nick b - Saturday, Apr 30, 2011 at 11:10

Saturday, Apr 30, 2011 at 11:10
So does cleaning carby fix the problem ????
Cheers Nick b

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Reply By: friar - Friday, Apr 29, 2011 at 16:28

Friday, Apr 29, 2011 at 16:28
Hello Mezza,Ihave the same generator,about 8years old, had a hunting problem when it wae new fixed under warranty, it does not get used for long perids, always drain all fuel out carby included,it always seems to surge when first used after long periods, my fix is to put it under nearly maxium load for about half an hour, this usually fixes it. Friar
AnswerID: 452747

Reply By: murrayman - Friday, Apr 29, 2011 at 18:26

Friday, Apr 29, 2011 at 18:26
Hello mezza Iff you had it from new it should have had a carby upgrade and also a ecu upgrade depending on the serial no. This was a real issue with the ef1000is genys and even now they are not totally stable. I sorted mine by changing jets and just recently the state svc manager said they have increased the throttle return spring pressure under the electronic governer by giving an extra turn on the spring and that is also settling them down. I am a yamaha dealer and some of these have just about drove me to drink. In saying that just being a yammy dealer at the moment will turn you in to an alcoholic. my ef 1000is has done over 2000 hours. cheers mm
AnswerID: 452765

Follow Up By: Mezza - Saturday, Apr 30, 2011 at 18:19

Saturday, Apr 30, 2011 at 18:19
this generator is an ef1000is. it has a number of numbers which include N432 and 7VV-24164-40 and was made in 2003. I have never returned the machine to the dealer I bought it from as he is 4 hours away rrd fm and when we are travelling lots further. It would be good to confirm if this is one of the models which should be upgraded. thanks for your help. PS this machine could also be up around 2000 hours, it was the main source of power for 9 month trip away running for up to 14 hrs a day. It is very economical running 14-15 hrs on 1 tank of fuel.
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FollowupID: 725586

Reply By: Rangiephil - Saturday, Apr 30, 2011 at 10:12

Saturday, Apr 30, 2011 at 10:12
Is it a EF 1000 or the latest model sine wave S ?
If the older one like mine I fixed the problem.
I bought it from ebay hardly used and it surged like mad. The older ones do not have an idle circuit and the governor controls the speed.
I did a couple of things.
First check that the hertz is correct at 50. Mine was at 60.
Second I emptied the tank and added fresh unleaded not E10
Third I cleaned out the carby . In mine the emulsion tube seemed to be partly blocked.
After all this it still surged, so I upped the off load speed a little on the governor and now it is OK.
I also always run some additional load like a 100- 150W light bulb if I am running a variable load.
Finally I added POR15 Fuel Stabilizer to the fuel.
I also try to run it for 15 minutes each month or so to use up any fuel sitting in the carby.
BTW there is a yamaha generator Forum in teh US which is helpful.
Regards Philip A
AnswerID: 452815

Reply By: MEMBER - Darian, SA - Saturday, Apr 30, 2011 at 14:36

Saturday, Apr 30, 2011 at 14:36
What exact model do you have ? As for my EF1000iS - I start it up every month and run it for 10 - 15 minutes - it gets little real use on trips - just there as an emergency power supply in case of poor solar input - this regular running avoids stale fuels and the associated troubles. Only time I had an issue was with a vapour lock in very hot weather - cooled it down with damp cloths and then ran it with the back cover off. Been good to date.
AnswerID: 452840

Reply By: murrayman - Sunday, May 01, 2011 at 13:10

Sunday, May 01, 2011 at 13:10
hi mezza, i will do a s/n search in the next couple of days and get back to you. From memory all 7vv models had a carby change, 7vw models already had the other carby on them. The other thing to watch for is iff you run it just sitting on the ground in dusty areas it will suck up the dirt and put a coating of dust across the ecu and they will do funny things then. Have had to clean out a few of these. Always sit them on a bag or a old peice of carpet or something. cheers mm.
AnswerID: 452911

Follow Up By: Mezza - Sunday, May 01, 2011 at 16:40

Sunday, May 01, 2011 at 16:40
thanks murrayman, Cleaned the ecu today to rule that out. will be using carpet in future. some dust and oil present on ecu. thanks for the tips. mezza
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FollowupID: 725686

Reply By: murrayman - Monday, May 02, 2011 at 18:20

Monday, May 02, 2011 at 18:20
hi mezza, i have some info for you, can you send me a private message with your email on this site and i will email you the service bulletins with the info you require on the carby. the 7vv no you gave is a part no for the sticker. the serial no will start with 7vv but that is explained in the bulletins. cheers mark
AnswerID: 453076

Follow Up By: Mezza - Monday, May 02, 2011 at 18:50

Monday, May 02, 2011 at 18:50
thanks murrayman, how do I go about sending you these details? mezza
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FollowupID: 725832

Reply By: murrayman - Monday, May 02, 2011 at 20:55

Monday, May 02, 2011 at 20:55
hi mezza, apparently you have to be a member to send mms. here is my shop email, it has pretty good anti spam things. mec@lm.net.au send me a email and i will reply with the service bulletin attachments. in the subject line put yamaha and it will get through to me. cheers mm
AnswerID: 453097

Follow Up By: Mezza - Monday, May 02, 2011 at 21:05

Monday, May 02, 2011 at 21:05
thanks murrayman will give it a try
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FollowupID: 725862

Reply By: G.T. - Tuesday, May 03, 2011 at 15:39

Tuesday, May 03, 2011 at 15:39
It may be your fuel can that you fill the genny from. It could have crud in it. Regards G.T.
AnswerID: 453160

Follow Up By: Mezza - Tuesday, May 03, 2011 at 18:24

Tuesday, May 03, 2011 at 18:24
Used a new container this last trip and try not to use the dregs. Have cleaned the tank on a number of occasions - as late as yesterday. There was a small amount of crud - I am amazed it can get past 2 filters - I fitted an extra one in line between pump and tap. The genny at the moment is running so-so.
I have the pilot screw screwed out about 2&1/2 turns which I understand is probably too far. I have had problems with the spark plug fouling and the spark arrester carboning up which I attribute to it running too rich. mezza
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FollowupID: 725948

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