When sorting out carb/fuel problems with old cars, the fuel-injection techs pointed out that ethanol is the real villain in most similar problems. It's the reason you can't use mo-gas in airplanes, for example. Most new fuel systems are engineered to resist ethanol rot, so it's possible that the older Kymcos may be using old-style neoprene lines and gaskets instead of the newer (ethanol-proof) Viton gaskets and O-rings (https://www.calpaclab.com/viton-chemical-compatibility-chart/) FAA doesn't allow ethanol in av-gas, but it's not easy to get; if you've ever used car gas with ethanol, it's too late. You have to take it all apart and start again!
Your opposition to EFI is well documented here JJJ - but most of us love it, and have had no issues with it or with ethanol laced fuel in our EFI vehicles.
We've another very veteran two wheel rider who has used the normal pump gas (w/ethanol) ,which we all have easy access to, in his EFI bikes and scooters for years with no problems.
The LIKE seemed to be fitted with a fuel line from a small batch sourced by the manufacture around the year 2012.
"Small batch"? - yes because the reported issues with this line have been very very few and seem limited to that era.
I see no reason to be concerned about ethanol fuel in any of our EFI vehicles.
My dealer certainly does not warn customers to go in search of ethanol free gas - they fill your first tank with SHELL regular down the block.
I'm no expert - but there are many vehicles in my area fitted with EFI and there are
no ethanol free pumps in this town....thousands are
not walking while their cars are lined up at repair shops,
nor are cars and motorbikes lined up down at the marina.
Stig