Honda eu20i generator.... premium or unleaded

Submitted: Friday, Mar 06, 2009 at 16:23
ThreadID: 66569 Views:9054 Replies:5 FollowUps:4
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Had a noise at loads 900w+ sounded like muffler baffle took it in to the Honda dealer, only 14 months old still under warranty and they said they would check it out.

Next call was that they thought it was a bearing and on inspection it was found to be carbon build up on the piston making the noise.

They asked how many hours had it done because this happens around 300hours but ours no where near that, then they said it can happen from continues idling which we always use good loads heron 2.2, heater, microwave and so on.

Then I was asked which fuel I used and said premium and told this has what caused the carbon build up.

Would this cause it what do other people use?


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Reply By: Member - Warfer (VIC) - Friday, Mar 06, 2009 at 16:28

Friday, Mar 06, 2009 at 16:28
Just Unleaded TW,But if its been sitting there for months i toss it with fresh stuff..

AnswerID: 352583

Reply By: Bushtrek - Friday, Mar 06, 2009 at 17:03

Friday, Mar 06, 2009 at 17:03
Well, first off you have been using UNLEADED. Premium in Australia is UNLEADED either at 95 or 98 RON.

Second, the minimum octane is 86, there is NO MAXIMUM.

Third, the higher the OCTANE the LESS carbon deposit formation under standard combustion conditions, irrespective of the combustion pressure (BMEP) and the operating load.

Fourth, the carbon deposits have to be analysed before they are able to attributed to fuel or ENGINE OIL origin.

"carbon build up on the piston" is reported. Where is the buildup???
Crown?, top land?, ring?, groove?, oil ring? Skirt?.

Is there associated cylinder wall polishing?? and if so where in the piston travel area is the polishing.

Once a competent engine engineer (not a trades mechanic) has looked at the parts then a proper diagnosis is possible and the actual cause may be determined.

OH, by the way, if carbon build up is fuel derived then it will be evenly distributed over the crown, the top land and associated top area of the cylinder AND DOWN THE EXHAUST TUNNEL.
It will not be below the top land, that is the province of oil degradation and the prime suspects will be oil ring tension, cylinder liner surface condition, and liner to piston conformity.
AnswerID: 352590

Follow Up By: Geoff (Newcastle, NSW) - Friday, Mar 06, 2009 at 17:12

Friday, Mar 06, 2009 at 17:12
Hi Bushtrek,
Thanks for that, interesting information to say the least!

I'm sure there is a whole lot more to it as well!


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Follow Up By: time waster - Friday, Mar 06, 2009 at 17:35

Friday, Mar 06, 2009 at 17:35
Yes thanks Bushtrek I'm not sure exactly where the carbon was on the piston all he told me was that that was the noise as the piston came up and the carbon was touching the head.

It burns no oil from change to change and blows no smoke at all but will ask some more questions on pick up.

I still think it sounded like the muffler so will be interested to see if it is still there.

FollowupID: 620786

Follow Up By: ross - Friday, Mar 06, 2009 at 20:11

Friday, Mar 06, 2009 at 20:11
I thought unleaded was more like 90-92 and Premium 95 ,although I know it differs a bit from servo to servo .

Ive only used unleaded in all of my small Japanese engines
FollowupID: 620813

Reply By: Member - Fred B (NT) - Friday, Mar 06, 2009 at 17:43

Friday, Mar 06, 2009 at 17:43
When I bought mine last July the RANms bloke, he was very specific about using unleaded and not premium. I don't remember his reasons, but he went to a lot of trouble to make sure I would use unleaded. If I get get the chance next week, I might pop in and ask him why.
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AnswerID: 352595

Follow Up By: Rockape - Friday, Mar 06, 2009 at 18:19

Friday, Mar 06, 2009 at 18:19
it would be good if you found the reason why he said that, cause our 95 premium is the USA's base unleaded.

I had to retune my Ryobi whipper snipper as it is set for fuel in the States and was hard to start and ran like a dog. I now run it on premium.

Have a good one
FollowupID: 620795

Reply By: Member - one way ticket (VIC) - Friday, Mar 06, 2009 at 18:58

Friday, Mar 06, 2009 at 18:58
hey TW, I had been running mine on unleaded and changed to premium and it wasn't happy at all. took it in for a service, didn't mention the fuel type at all and when I picked it up they told me not to ever put premium in because the engine was to small to handle it
AnswerID: 352604

Reply By: Member - Nick (TAS) - Friday, Mar 06, 2009 at 20:46

Friday, Mar 06, 2009 at 20:46
We had a larger Honda generator(not sure of model) come into the workshop that was used in a mr whippys van.It developed a rattle and locked up.Pulled it down and found carbon build up on the piston that bad that it locked it up.Cleaned it up and good as new.Talking to the Honda dealer, they said it was caused by not using Honda SAE30 oil.Never saw it back and mr whippy is still doing the rounds out here.
AnswerID: 352631

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