HAVE A GENNIE PROBLEM(not everyone's cuppa I know)

Submitted: Sunday, Mar 22, 2015 at 18:45
ThreadID: 117177 Views:2765 Replies:14 FollowUps:4
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Have a slight problem with my Yamaha 1kva Inverter Generator, in the way it is running
Give it the 5 minute warmup as recommended, with choke out, but once it "settles"and i have pushed the choke in it doesn't want to run smoothly. In fact it carries on like when running it out of fuel after use, up down up down. If I pull the choke half way back out (or thereabouts) then it runs ok with barely a hiccup. This happens whether under load or not. Am booking it in for a service, but just wondered if there may be a simple answer. Only thing I can come up with, is that I maybe have left it too long between startups.

Any ideas appreciated
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Reply By: futch - Sunday, Mar 22, 2015 at 19:00

Sunday, Mar 22, 2015 at 19:00
try resetting choke cable.. when you push it in possibly going back over centre. take off air filter to check and adjust.
AnswerID: 551412

Reply By: Bob Y. - Qld - Sunday, Mar 22, 2015 at 19:21

Sunday, Mar 22, 2015 at 19:21

Reckon you've got a bit of muck in the carby, and it's blocking the jet, and engine is starving for fuel. That's why when you partially pull out the choke, it enriches the mixture, and all good again.

Let them know at service and they might even fix the problem for you?


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AnswerID: 551414

Follow Up By: Bigfish - Sunday, Mar 22, 2015 at 19:40

Sunday, Mar 22, 2015 at 19:40
Reckon your on the money. It will be some sort of fuel blockage. I have had it happen to my Honda 2kva and my 5kva Yamaha. Sounds like its "hunting" all the time.
FollowupID: 836879

Follow Up By: garrycol - Sunday, Mar 22, 2015 at 21:01

Sunday, Mar 22, 2015 at 21:01
I agree too
FollowupID: 836887

Reply By: pop2jocem - Sunday, Mar 22, 2015 at 19:45

Sunday, Mar 22, 2015 at 19:45
Yep, as others have said, it sounds like a partially blocked jet.

Leaving fuel in the carby for long periods of time can cause deposits to build up as the petrol evaporates and leaves a residue.

AnswerID: 551417

Follow Up By: Member - johnat - Monday, Mar 23, 2015 at 08:57

Monday, Mar 23, 2015 at 08:57
Was told the following couple of pertinent facts by a "small engine repair" specialist with 25 years experience.

1. Modern fuels have a "shelf life" of around 30 days. Storage beyond that will result in the petrol part evaporating off and the remaining additives, which do not evaporate as quickly, turning your fuel into gunk. That will a) not burn well, and b) clog jets etc in the carby.
2. 2-stroke oils come in two types, depending on which engine you are using. Engines that rely on mixed fuel/oil need to have a "mixer" oil added to the fuel - and no need to shake the container as the modern 2-stroke oils are formulated top stay in solution. Engines that inject the oil direct need an "injector" oil, and injector oil will not mix into fuel.
3. Never run a 2-stroke engine till it runs out of fuel, as that wiill mean the last few revolutions will be "metal-to-metal" without lubrication. And, the first few revs after refilling will also be "metal-to-metal". Increased wear.
If storing for a while without use (although best to run a couple minutes every couple weeks) stop engine and drain fuel tank (or turn off tap). That way the moving parts have an oil film.
FollowupID: 836905

Reply By: Ron N - Sunday, Mar 22, 2015 at 19:48

Sunday, Mar 22, 2015 at 19:48
Kevmac - Grab a spray can of "throttle body and carby cleaner" (about $10 from any auto parts store), turn fuel tap off, and then drain the carby bowl and disconnect the fuel hose leading into the carby.

Replace drain plug in carby bowl (or bowl itself, if it doesn't have a drain plug), then squirt a good dose of TBACC into the fuel inlet pipe that leads into the carby.

Replace hose, ensure tank has adequate amount of good fresh fuel in it, and crank it up.

TBACC is half acetone and half methanol and it will generally clean out carby jet orifices, fuel deposits and gunk in the passageways of the carby.

If the engine doesn't run any better the carby will need to be dismantled and physically cleaned with brushes and perhaps even a bath of phosphoric acid (mag wheel cleaner).

(P.S. - Don't breathe in the TBACC and only use it in a well-ventilated area where there are no possible sources of ignition. This stuff is potent).

Cheers, Ron.
AnswerID: 551418

Reply By: kevmac....(WA) - Sunday, Mar 22, 2015 at 19:50

Sunday, Mar 22, 2015 at 19:50
Thanks everyone.All those thoughts have crossed my mind. Maybe one use i got impatient waiting for it to die and hit the kill switch and left fuel in carby.. Oh well, phone call to place I bought it from in the morning to book a service. Just hope they can do it quickly, as the good lady wants to go away for a weekend while I have to work.
Thanks again everyone !
AnswerID: 551419

Reply By: B1B2 - Sunday, Mar 22, 2015 at 20:29

Sunday, Mar 22, 2015 at 20:29
Did you remove the spark plug to check if it is wet or dry? I would change it any way.
Have a look at the spark as well.
With your symptoms it would probably be dry, confirming lack of fuel. All good info to diagnose the problem cheaply.

Good Luck,

AnswerID: 551422

Reply By: laurie b1 - Sunday, Mar 22, 2015 at 20:57

Sunday, Mar 22, 2015 at 20:57
I am just wondering if you might have a breather in the fuel cap which you turn off for travelling and maybe havn't opened that, which would stop fuel flow.
Just a thought. Hope it is as simple as that.

AnswerID: 551424

Follow Up By: Life Member-Doug T NSW - Sunday, Mar 22, 2015 at 21:39

Sunday, Mar 22, 2015 at 21:39
Exactly what I was thinking, my Gennie has a lever on the cap for breather. If the tank can't breathe then it'll stop after a few minutes.

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Reply By: Rangiephil - Sunday, Mar 22, 2015 at 21:14

Sunday, Mar 22, 2015 at 21:14
I have an earlier non inverter Yamaha 1KVA which has the same motor, and mine does exactly what yours does.

In my case and I think in yours you will have to remove the carby and clean the main jet and emulsion tube.
It is a pretty simple job, which I recently did and now mine is going like a train again with no problems.

IMHO, it is not really the main jet but the emulsion tube that gets gummed up. I always turn mine off by holding the throttle lever just above the point that grounds the ignition so it starves and it still seems to gum up. I also use fuel stabilizer.

I think that it stalls before the carb is completely empty.

Regards Philip A
AnswerID: 551426

Reply By: MEMBER - Darian, SA - Sunday, Mar 22, 2015 at 22:31

Sunday, Mar 22, 2015 at 22:31
For what it is worth....I have had the same unit for about 10 years....Not used extensively- just the occasional chargings.....always started with choke, but then I push it back in straight away and the gennie is happy....have never run it dry either- just switch it off and close the fuel tap. All good so far. They are a great unit....BOL with yours.
AnswerID: 551432

Reply By: Honky - Sunday, Mar 22, 2015 at 22:38

Sunday, Mar 22, 2015 at 22:38
I have a non Honda generator that I do not use much since I get the Honda.
When I start it it runs very rough and I use the choke to keep it running, most likely due to stale fuel.
I drain the old fuel, put in a good dose of carby cleaner that you use for cars in the fresh fuel and run it on a small load and increase tight up to max load ( non Eco with the governors wide open) as it starts to clear.

AnswerID: 551433

Reply By: Mudripper - Sunday, Mar 22, 2015 at 22:49

Sunday, Mar 22, 2015 at 22:49
Have had the same problem as you describe with my Scorpion 5.5kW generator in the past. Turned out to be a partially stuck needle valve. Pulled the carb apart, blew it all out, reassembled and it ran like new.

Now I'm in the habit of draining fuel after use via the drain plug on the bottom of the carb bowl. Our generator is only used as a back-up for when we lose power (in rural Tassie, that's quite often in fact!)

AnswerID: 551435

Reply By: Member - Tony H (touring oz) - Monday, Mar 23, 2015 at 02:11

Monday, Mar 23, 2015 at 02:11
Have a look at this http://www.kedronownersgroup.com/forum/index.php?showtopic=2369
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AnswerID: 551439

Reply By: Krooznalong - Monday, Mar 23, 2015 at 14:29

Monday, Mar 23, 2015 at 14:29
Bought one a few years ago and it did exactly what you describe from day one. So I took it back under warranty and they said "nothing to worry about". Sold it recently and it was still running the same way.
Anyway it never seemed to affect the stuff it was running so I guess the "nothing to worry about" advice was OK.
AnswerID: 551458

Reply By: Member - Nutta - Monday, Mar 23, 2015 at 20:00

Monday, Mar 23, 2015 at 20:00
Run it without the air filter and see how it goes.
AnswerID: 551495

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