Engine maintenance, by Sam!

So our engine is a Yanmar 3gm30g 27hp, original with the boat, so it's 30 years old.  These are great engines and will run forever but you need to look after it and maintain it.  I began with having a look at the impeller in the raw water pump to find that there was one leg missing.  I managed to find it in the heat exchanger!  Changed the impeller.  Then realized there wasn't quite enough water coming out, in other words the pumps wasn't pumping enough.  Upon inspection I realized the pump cover was worn and would not create a vacuum.  So we changed that.  I also found second hand an alternator and a starter.  I also purchased all the fuel and oil filters we will need for the next year as well as a bunch of engine oil.  Cooling fluid as well, spare raw water pump gaskets.  While cruising out we noticed that the engine was slightly white smoking.  White smoke is a sign of water or contaminant in the fuel and restriction in the mixing elbow (where the exhaust meets the cooling water). So I decided to empty the fuel tank with a oil extractor through the oil level hole in the tank, one gallon at the time, took all night!  The fuel smelled bad and had water in it. I also suspect that the previous guy put way too much stabiliser in it as it didn't smell like regular diesel.  Also found an old fuel cap chain in the tank!  So emptied it, shop vacced the bottom.  Changed the primary and secondary fuel filters, changed the oil in the engine and transmission, changed the oil filter.  Put new oil everywhere.  Also replaced the mixing elbow, it was badly corroded and 3/4 blocked, which did not help!  Now everything is new and clean so if there are problems in the futur they will be ours.