I just bought a 1990 xlt f/250 4x4 and it ran great on ride home.rinsed motor.nxt day fired it up.blowing dark blue exhaust.so rich my eyes water.chkd plugs&two so far are black why?

Sounds like you might have some bad plug wires that the water caused to short out or maybe water in the distr. But that just a guess. I never use water to wash off a motor any more cause it gives the electrical components hell if they nor perfect and still factory sealed. Might try removing the distr cap and wiping the inside down with a dry rag. At least that's where I would start.