how easy did it start after the service? i would think that if there was air in the system it would be very hard to start. did you bleed the system after doing the service?
also what EXACTLY did you replace - both fuel filters (primary and secondary?), is the motor fresh or raw water cooled? did you replace the coolant if fresh water? did you replace the thermostat?
how long before the heavy smoke turned to light? for me, now that we are having temperture swings from 70's -> 40's - when I start up motor in the morning i get a little light white/grey smoke but it goes away after a min or two - likely due to some condensation in the exhaust or water lift muffler i guess.