Thermostat Stuck open?

[Chad52]

First, I have a 2008 210 TE with the 343 Excalibur Engine.

Last week, while out on the water, I noticed that my temperature gauge was showing that I was running cool, about 110 F while underway (3-4k RPM). The surface river water temp was 88F. I initially thought that the gauge might not be reading correctly, but when I stopped, the temp would rise slowly to about 130F+. When I would get back underway, it would drop back down to around 110F again. Both digital and analog gauges were reading the same thing. Typically, when the engine is warm, I get a solid 160F. So I'm assuming at this point that the thermostat is stuck in the open position and needs replacing. Do you guys agree with that assessment? Anything else that I need to check out?

Also, what is the part number for the correct thermostat to order? R026002 (160F)?

Thanks in advance...

Chad

[ronskal]

Sounds like it may be stuck open. You have not had an impeller go bad recently? They can leave rubber bits in there (not by experience, others have reported this). Get a new one and gasket from nautiqueparts.com.

[jhersey29]

The last over heat I had due to an impelled explosion I had a similar reading. I had replaced everything including the thermostat. The heat still would not rise. I ended up pulling out the water temperature sender. I could that the plastic washer that ws used on my hose hook up had melted and a large amount of it cooled to attaches to the sender. I scrapped off the plastic from the sender, put it back in and it worked perfectly. Now I use a rubber washer on that hose attachment. Might not be related to your experience but could also be the sender. They are easy to check with a pot of water, ohm meter and a cooking thermometer.
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[Chad52]

OK, next question about the same subject...

Due in part to both my laziness, and my GF undertaking a cabinet staining project that consumed the other half of my garage, I still have not replaced my thermostat. I've ordered and received the kit from NautiqueParts.com, because I am a pro at ordering things off the internet. I just haven't installed it yet.

So the boat now runs at a very cool and stable 106-110F with the thermostat stuck open. To me, after several times using it, it feels like the boat actually has a bit more power. It seems to get out of the hole quicker when loaded now than it used to. Is this the expected behavior from an engine running cooler? What would the mechanics on here expect to see from an engine running at cooler temps? So far, is the only drawback that the heater won't be as hot now?

I'm planning on cracking the whip and getting back control of my garage by the weekend and getting the thermostat changed out. Just wondering what the ramifications of running the engine cool are.

[Nautiquehunter]

A cold engine will be recognized by the computer and the fuel and timing will be adjusted accordingly . The Tstat in your boat is a 15 minute job you should be able to see if its stuck open. If not drop it in a pot of water with a thermometer and see when it opens as you heat the water . The stat will have the opening temp stamped on it should be 165 degrees . Note the basket will face up when installed correctly.

[Chad52]

Thanks, but I was really looking for tech info on how the engine performs at lower temps rather than how to replace the thermostat. Any info that pertains to the previous post?

[jhersey29]

Thing I would consider with stuck thermostat for versus performance. The exhaust manifolds may run hotter since the engine will be drawing water and warming it up instead the thermostat closing and allowing fresh cold water to the exhaust manifolds. The engine oil won't be as warm so maybe evaluate the oil viscosity. Fuel consumption may be higher. Not sure about these things but they come to mind.
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