So I bought a used 2004 ET4 (3300 miles) and I rode it about 100 miles over the weekend with ALMOST no issue.
It was having trouble idling so I adjusted the idle up. After that I accidentally overfilled the tank with 87 octane fuel. Now I know it needs premium, but this is a learning process.
I rode it today and it started cold with ease and seemed to run well. I rode it back home tonight and my wife asked me to run to the store so I took the vespa. It had trouble starting while it was already warm and will not hold an idle now. It just sputters and dies. Then it is hard to start and I have to rev it to get it to stay running. As soon as I let off the gas it sputters and dies.
In another post I mentioned that it makes a squeak, grunt, lame duck, harmonica sound every few seconds after being shut off. Evaporator system is what was mentioned.
Now I am thinking my idle may be set wrong, overfilling caused problems, low octane gas is causing problems, and/or the evaporator system needs to be replaced or just removed altogether.
I am not sure what I should do first. My feeling is that in the morning when cold it would start again, but I am not sure.