engine not firing on # 1 cyl?

I just rebuilt a 18 HP BRIGGS ENGINE AND IT HAS GOOD COMPRISSION ON BOTH CYL. . NEW PISTONS, RODS, VALVES THE WHOLE WORKS.iT RUNS BUT HAS A LOT OF BLACK SMOKE AND # 1 CYL DOSN'T SEEM TO BE FIRING. wHEN i REMOVE THE SPARK PLUG IT INDICATES GOOD SPARK.Also when running I pull plug wire off it keeps running but when I pull only the #2 plug wire it dies. What do toy think?