I got a used 4/3500 direct drive pump and water drips pretty good from somewhere between the body and head. It does this even with the engine off. Doesn’t seem to be mixing with the oil, are we talking a cracked part?
Are you talking about a leak between crankcase and manifold/head? If yes and it’s hooked up to pressurized supply then maybe cracked plunger
How difficult is it to separate the head and check?
8 Allen head bolts and two minutes of your time.