Recently I re-engined my 21", replacing the faithful but tired old Briggs Quattro with a new 6.75 Briggs OHV. This is my first experience with OHV Briggs. Overall the engine is great -- runs very smooth, plenty of power, and impressive fuel economy. But every day, on the first 'cold start' of the day, it will puff out a cloud of blue-white smoke. Does this for just a half-second, then the exhaust becomes clear and stays clear afterwards. Subsequent starts throughout the day don't give the smoke. The engine runs great, and burns no oil during the day. Is this a normal thing with OHV Briggs? The engine is still fairly low hours, so is this maybe a break in thing?