discolored

Water PSI good (17PSI when running hard) do i just not have enuff water volume? Or could i be reading air psi? I have water pickup on the bottom of the boat. Thank you

My buddy just pulled down his FE motor. Here's a pic of the rods. Notice the one that's not like the other ones? Hard to miss the coloration. Is this normal? He thinks not heat related because the discoloration is perfect. I'm not a real big believer in "uniqueness" of one in a set...