Multiple Questions:Temps,Cocks and Rodes

[SEEKER]

Alright, I've been running our 2011 R25SC which we bought new for a few years now and we have about 450 hours on our Yanmar 150..4By yada yada...so I feel that our engine is now broken in and I'm starting to ponder some questions.I'd thought I'd send it out to the Tug Nut Universe and see what comes back.

1. Temps: I've replaced my impeller at 250 hours and one fin had a crack in it but the impeller and fins were intact, no rubber was missing or broken off. I replace my engine zincs every year and I'm always surprised at how corroded they are, I have not flushed my heat exchanges or replaced my coolant although coolant replacement is on my list before next season...here's my question; Those with the same engine, what are you folks seeing for normal engine temps? At cruise, around 2500 RPM I'm at 194 F, I've always held steady at 194 F even when I've got some juice on and I'm at 3400-3500 RPM until this year, now I'm seeing 196-197F when I'm above 3200 RPM. I'm wondering if those corroded link particles are starting to clog my heat exchanger or maybe my coolant is losing some moxy? Or I'm over concerned?

2. Cocks: Now I'm not comparing but how many of you close your seacock when at anchor? I ask because just recently I pulled 4 people off their boat before it sunk due to a hose clamp that popped off their heat exchanger. If you do, I'd be interested to hear why.?

3. Anchor Rode: I've got 100' of chain and 200' of nylon, no swivel...I'm just a traditionalist that way. What are your thoughts on how often to replace the rode or at least the nylon section?

Thanks. Look forward to some feedback.

 

[knotflying]

I have the 4BY-180. Same engine just a tweak of the computer to get the extra HP. My temps are similar to yours. However, when in warmer climates and water at WOT I go up to 204. I am pretty sure the thermostat does not open until 206 degrees.
At anchor my sea cocks are open and probably should be closed. You can never be too safe.
I check my rode for integrity, but never have thought about a standard replacement interval, so comments on that should be interesting.
I change my antifreeze every year. The reason is that if you really want to get all the antifreeze out you have to remove the heat exchanger. I don't know about anyone else, but there is no way I am going to do that. When you drain the antifreeze from the petcock on the side you get about 1-1/2 gallons of antifreeze out. Yanmar's maintenance schedule suggests replacing the antifreeze every two years. My theory is if I am only getting about half of it out each time, doing it every year should replenish it often enough so as not to loose the anti corrosion properties and the lubrication.