This is an example of the damage caused in a carburettor by E5 5% ethanol that is in regular pump petrol. Ethanol is aggressive to metal which causes corrosion which then results in poor running and starting problems.
This is a regular sight in our workshop with customers using regular pump petrol and not being able to start their machines. As you can see it has A LOT of water in it. Ethanol will naturally absorb moisture from the air.
This is exactly the same spark plug which are both one year old. The one on the left has been running on regular pump petrol and you can see the carbon build up on the end of the spark plug. The spark plug on the right has been running on alkylate petrol and as you can see has a much lower carbon build up. This is because Alkylate petrol is a clean burn fuel.