Quote:
When cold started, the fuel will not combust very well which results in a "lean" condition although the mixture will be good once the engine warms. Spitting up through the intakes is typical after a cold start. Once combustion chambers warm up a little, atomization/vaporization is much improved and the mixture will be more fully developed which will then create a more combustible mixture. I see this when starting my test engine, AFR will be in the 17s and after about one minute the AFR will be 11.5, this is without adjusting any setting on the carb.