Bad exterior Paint?

[Boar]

Have been painting the exterior of my house an one area on the old 12" siding has been truning my brown paint to yeelow stains, it looks like the yellow staining is leechin from the siding abouve but I dont think so. I make sire the paint is mixed well an dont think the humididty is to high. This was the second coat too.Did i paint to soon aftr the first? I painted over the stain an it came thru again. Bad paint? do i have to prime with a stain blocking primer to cover it up? I did prime before I painted. Any help would be great. Boar

[crothmeier]

id try a stainblocking primer like kilz or zinsser. that should do the trick. .