Reply To: Merc 400 teardown looming

[Don]

I’m not a merc guy, but that is a beauty… Hopefully a merc guy will weigh in, would be a shame to give up on this engine. Normally, I would recommend pulling the head and having a look, but I know the head is not removeable… When you say you lost the impeller, does that mean the blades broke off? If so, did you find all the pieces? If so, I would be inclined to replace the water pump and get the engine running. The overheat may have just left the engine real dry, perhaps the compression will come up after running with some extra oil in the mix…. This might be wishful thinking, but worth a try….