There is one more thing I forgot to make note of. The spark plug wire can get loose if you hit a big bump. I did that one time and the engine began to idle poorly and then quit. It would restart and then do the same thing again. Plus there was a little backfire. I happened to be close to the dealer that day, stopped in and told them what happened, and the service guy went right to the spark plug wire. He told me it was a known issue with some Vespas but especially the 150s due to a spark plug wire that is short and prone to pull loose. No recall is planned because it is said it does not constitute a safety problem.