Taking care of a Yanmar 4JH3E, 55hp

You asked the time period when we had the 1400 hours on our engine. I was at about 5 1/2 years. So your insurance company is pretty close to the mark. NOT changing the elbow in time can cause bent valves and other not nice things to happen to your diesel.
I should note that a mechanic was surprised at how much "Clay" coated the antifreeze side of our heat exchanger. He said that it was possible that upon commissioning the engine was filled with the specified amount of antifreeze concentrate and then topped off with distiller water. Leaving the engine circulating system to mix it. He said this was a No-No because the antifreeze concentrate would "Scale" onto the cooling tubes as the engine heated up and before the fresh water side was properly mixed. Mixing antifreeze and water prior to dumping it into your engine was the proper procedure.

You are doing fine LarryM!
I'd add the valve adjustment too but I'm a little strange...
One note, the exhaust riser used is difficult to inspect if you do not look carefully. You have to look way up at the top where the water is injected to see where the blockage happens. I pull it off and look up into the side that connects to the hose. What you will find is that the hole the exhaust must go through becomes smaller and smaller in time. This can and does lead to a change in exhaust tone and eventually more and more black smoke! Ask me how I know...
Anyway, it is easy to see if you get it out of there for an inspection.
Bruce

Larry,
When I repowered I bought ($750) an all SS high rise unit and 10 years later (now) i'm glad I did. I had a 3HM35F in an Albin and replaced several over a period of 6 years.