Thanks for the good advice. The problem seems to be enironmental rather than mechanical. It played just fine last evening. BTW, I'm playing a cheapie single row diatonic...the best $250 bucks I've ever spent! I really agree with leaving it out of the box. It helps me play/practice more often.
I dont know if your box is new or not, but another thing I noticed after I redid the leathers and felt on the flappers is it took a little playing to seat the valves well.