Do you need to primer concrete block when using exterior masonry paint?

I need to paint a block wall and was wondering if I have to primer it first, or just wash it with a hose first?Do you need to primer concrete block when using exterior masonry paint?
you need to seal it or prime it or else those blocks will soak up that paint like a spongeDo you need to primer concrete block when using exterior masonry paint?
The long answer 2 your question is....No! you only have to seal surfaces that are crumbling or flaking, dont hose wall just brush of any dust %26amp; loose material the have fun painting the wall %26amp; not yourself! lol.