Engine Paint Question

if it works like car paint ....I wouldn't wait till the primer cures .....when it cures, it skins over and the outer resin does not stick as good to paint ....that's assuming its like epoxy primer .....I would wait till it "flashes" and then spray the color coat, the primer coat will be still soft enough to accept the color coat and bond but not too much solvents left .....they are from the same manufacturer and same system so there wont be an overload of solvents after the primer flashes.