I changed my process for dealing with storing our EU generators after use after one of our EU 1000s would not run without the choke on with original Stabil treated gas that was a year old. No amount of runnning it with Sea Foam in fresh gas cured the problem. Took it to the Honda dealer for a carb job. I now treat all mid octane gas used in our generators with Stabil Marine and (within a month after last use) any left over gas is removed from the tank and the carb is drained using the drain screw. I crank the engine until it will not run at all. This has worked well for me for 7 years.