Moped question - help needed

[Filbert]

Me and hubby both own Honda Scoopies 75cc. Mine has no probs starting, but his is a different story. When he presses the ignition button it makes a high squealing noise. When it does get going, there is an enormous amount of smoke coming out of the exhaust (quite embarrassing as we live in a busy area). It billows out for about a mile then disappears. It doesn't need oil or petrol. Does anyone have any idea what it could be? The garage told him just to use it more, but he uses it the same amount as I use mine and I don't have the problem.