In the UK, as of September, forecourt standard unleaded fuel will be classed as “E10” which means it has a higher Ethanol content (10%) than it currently does (5%). this could cause a number of problems for outboard owners as the new standard of fuel will probably lead to internal corrosion, particularly in the Caburettor. In all cases follow the engine manufacturers’ guidance as I’m no scientist but from what I’ve read, I will be using Super Unleaded from now on in, which contains equal to or less than 5% ethanol.
The majority of engines I get in are with me because of carburettor problems, generally caused by a build up of grunge over time, my reading of it is that E10 unleaded will make that even worse, I would suggest you take a read up on the subject and before you put your engine away at the end of this season, that it is filled and run with Super Unleaded.
Take a look at the petrol pump in your garage before you use it, there should be a sticker on it telling you if it’s E5 or E10, if the unleaded pump is E5, it’s fine, it’s what you have always been using, if it says E10, use the super unleaded.
E10 fuel is less stable than E5 so it has a limited storage life before it begins to break down, E10 petrol will attract moisture from the atmosphere so will cause internal corrosion in your engine, particularly in the carburettor. In short, E10 fuel is not a good choice for your outboard engine, if you have to use it, make sure you use it and that’s it, I would strongly advise against leaving E10 fuel in your engine for any storage period (longer than a day TBH)
Thanks All