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I have a 3.5kW generator here on which the “car petrol” has eaten the entire level gauge assembly 
It did take a few years though.
Peter wrote:
eaten the entire level gauge assembly
It’s not a Wolf 3500 by any chance? Ours did exactly the same thing. The dissolved fuel gauge plastic meant I recently had to get the carburettor, fuel line and fuel tap replaced in turn before it ran happily again.
Researching this problem at the time, thinking it was the result of old fuel, I found a friend had done consultancy work for a lawnmower repair specialist. A lot of their work is in spring when people try to start their mowers after the winter, and find they can’t. All they do is clean the fuel system, put in fresh petrol, and voilà.
The business owner uses Briggs and Stratton Fuel Fit Stabiliser (Amazon) in his personal mower, which should extend the shelf life from 3-6 months to 3 years. When asked why he doesn’t recommend it to his customers he said, “I’d have to fire at least a third of my mechanics, and I wouldn’t have a business after a couple of winters”.
I got some this year, and will see what happens to the mowers and generator next spring. No idea how compatible it is with aviation.
The main enemy in MOGAS is ethanol and it is in most fuel sold in the UK, the only MOGAS sold in the UK without ethanol is the top grade of fuel from Esso.
Most of the motorcycle fraternity use this just before the bikes go away for the winter as it prevents most of the usual problems with MOGAS storage.
I understand the sea tankers don’t carry alcoholed fuel, and the Inverness Depot doesn’t add it. Slocal suppliers have alcohol free EN228, some have alcohol in it. We test after using sources we expect to be alcohol free.
