Honda eu20i generator.... premium or unleaded

Just Unleaded TW,But if its been sitting there for months i toss it with fresh stuff..

Cheers

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.

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.

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
hooroo

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.