..."they have had a problem with them on starting..."
Translation: "I'm too dumb to know what to do to fix it."
Assuming this is a carbureted Merc, here's what to try:
Your motor has an enrichener valve that dumps raw gas into the motor to start it when cold. It's either not opening, or you're not pumping the bulb enough (or it could be defective) for fuel pressure to build up. No pressure, no gas getting into the motor. Poor cold starting.
Try this: Pump the bulb up HARD, then see if that helps. If not, see if your enrichener has a manual 'valve' deal on it (usually red in color). Flip that (which does what the solenoid inside is supposed to do) and try starting her again. If that does it, see if the solenoid is getting juice and, if so, replace the valve.
Then find yourself another mechanic!
Jeff