I have a Cimatti City Bike, which has a Morini engine (I don't know they year; how can I find out?). My folks got it at a garage sale a long time ago, and used it a little bit. Then it sat in the basement for about ten years. Finally, I decided that I wanted to fix it up. So I cleaned out the carburator and the gas tank, which had been covered in oil gunk from the gas, and got it working. I used it on and off for about a year, then went off to my first year at college. I got back this summer, and started using it again. Or I tried, anyway.
I took it on a trip of about 5 miles, and then parked it for the night. The next day, it won't start. I've been trying to get it working again for a while now. After an hour or so of non-use, it will start up easy and run for about 20 seconds, then die. After that it won't start again, except for one day when I was pedaling it up and down the road trying to get it to start, and it would start every once in a while, run well for a few seconds and then die. Sometimes it would feel like it wasn't getting enough gas. Sometimes it would feel like was getting too much gas.
I've cleaned out the carburator a couple of times. I've mixed all new gas, and drained all of the old gas out of the system. I've checked for a spark. I've checked the gas flow from the tank. I've looked at the float, and there's nothing obviously wrong with it.
From what I know of the moped, it seems like the float is the thing that would cause a problem like this, but I don't know enough to be sure that its the problem.
Any tips that people could give me would be welcome.