2165 Briggs 16hp Vtwin Smokes bad when started
 

This is driving me nuts. When you first start it it smokes up the whole neighborhood, then after 5 minutes of running it is great, no smoke. Always starts and runs good. Both sparkplugs have the same amount of soot so it is not confined to one cylinder. Valve seals would just be a puff & they appear to be intact. Does anyone have the same problem and a solution?