project: water pump impeller, high pressure flush, and water jacket side plate

Just after I got the lifelines fixed, and then the starter fixed, we have a new problem: chronic overheating. I did my research and I'm starting an overhaul of the cooling system.

The cooling system on the boat is pretty cool, it takes sea water and runs it next to the engine, inside the block next to the pistons and then spits it back to the ocean. No coolant, no anti-freeze, no nothing.

I took out the old impeller, which didn't seem to be in such bad shape. I also took out the thermostat and cleaned it up with some vinegar. Stuff is amazing! I tested the thermostat in a pot of boiling water and it opened and closed as it should.

Some comments about the water pump impeller - in the shop manual for the engine it says that the water pump impeller shaft seals should be placed with the metal side in a specific way to the impeller. Well, that must have been some kind of inside joke because the whole thing is made of metal! The other problem was that the reality of what I was looking at was at odds with the shop manual. What I was looking at was exactly opposite of what the shop manual called for. What to do? So, I called Uncle Jack and then tech support and got all straightened out - the side that is all one piece of metal, the side with the writing on it, is the metal side.

Then, in preparation of a high pressure flush (not much more than hooking up a garden hose to the engine and giving the inside a good rinse) I took off the starter and the alternator. Wow. Corrosion Corner! I thought the stuff I could see was bad, but this was really bad.

Then, just to see, and since I had the gaskets anyway, I decided to remove the water jacket side plate. (The water jacket, as I understand it, distributes water mostly evenly across all four cylinders.)

As soon as it came off I called Uncle Jack. He never did a high pressure flush, nor did he do an acid flush. So that means the engine has been running for at least 11 years with no kind of flush. And that is if the owner before Jack had done it right before he sold it, which it seems to me, is pretty unlikely.

When I removed the bolts for the water jacket side plate, water rushed out. When I removed the bolt for the aft drain plug, which is lower than the water jacket side plate, I got no water. I thought, "that's odd." Well, it's because there was so much sediment in the block was so thick, and so deep, it was blocking the drain hole.

This engine desperately needs a high pressure flush and an acid bath. I'm using vinegar for the acid bath as it seems more enviro- and Jar-friendly.