I have a compressor that had this problem. I think it is a typical
problem due to the high torque required when the oil is cold and the
V-belt is stiff. I changed the belt from an old style V-belt to a
thinner, more flexible one and after that I could put a larger pully on
the motor and still get it to start in a cold garage. A cold, stiff
V-belt sucks a lot of power. Also, the line from the breaker panel to
the garage is usually quite long and in a 115V line, probably not the
heaviest gauge. Since you have a 220 V line, I would think that that
might not be as big a problem, especially with just a 2 HP motor. As
Mike said above, the pressure relief valve could cause the problem.
When I had the problem, I often held the valve open manually (not all
can do this) and that would allow the motor to come up to speed
unloaded and warm the parts up so it would run normally. Not the best
solution I will admit.