BIG MISTAKE. Which mechanic is this ? Do you know he swapped parts ? If so which ones ?
As far as Golimar is concerned, the guys there are the biggest Chorrs. Never leave your vehicle there if you don't know person well enough. They are known to take out original stuff and either sell it or put it in their vehicles.
What sort of smoke is it ?
Is it white smoke ?
Has your MUTT's engine been recently rebuilt ?
Is your MUTT consuming engine oil ?
Startup smoke is usually attributed to weak rings. When the engine heats up and the rings expand, the smoke vanishes.
Your MUTT should also be consuming engine oil if this is the case. Check and let me know.