Help troubleshooting please,engine temp

[Neil]

Hi All,
We have the 28 TE 1997. Yesterday was our maiden voyage! We had an alarm sound whenever the engine temp came close to 200. I was keeping it under 18knots, about 2700 rpm. So I dropped it to 16 knots about 2500 rpm and no more alarm, engine temp was at 175. Is that an unsafe temp? 200? Seems low to me. Or is it an alarm problem? We just put in a new thermostat.
Second problem, thank you for your patience.
We were only showing 11.6 volts while steaming home. Newish battery,newish alternator. After being plugged in dockside the dash read 12.5 and the charger was saying the batteries were charged. Shouldn't I be at 14-15 v when I'm running? Sorry about the newbie questions, and thanks for any help!
Neil

[special k]

i just did a rydlyme flush on my raw water side and dropped running temp by nearly 10*. sounds like your coolers need attention.

cruising speed temp now around 175-180 for me

2002 28te 6lp yanmar

[jleonard]

Did you get all the air out of the cooling system after you put in the thermostat?
The ridlyme (or equivalent) is a good thing to do. Also check to make sure the lid on the raw water strainer is sealed. Use grease on the threads and/or o ring.
Regarding voltage, yes it should be up around 14 when cruising.
Does your engine have an air intake heater? If so they take a lot of juice and will draw the voltage down.
They are supposed to cut out once the engine warms up a bit. But sometimes they stay on you'll have to check that.

[catalina_mike]

I took my Alternator to a auto electrical shop and had it rebuilt. My voltage regulator got blown somehow and I didn't have a volt meter in my old dash so I never knew. Charges great for now.

[RobS]

When discussing rpm's and operating temperature it would be helpful to know what engine..

[Neil]

It's a peninsular 6.5, 310 hp.

[Neil]

We did just flush out the cooler and put new gaskets on it. Newly rebuilt fuel injector pump, alternator is just over a year old, one batterie is just over a year old. Thanks for the tips, I guess we are bringing the mechanic back.

[Jeremyvmd]

Yea something sounds very wrong with that setup. I would bring the mechanic out...

[doughat]

Might one simple common cause for both problems be a loose belt(s)? Was this already checked?

[Tom Alby]

Do you have enough discharge from the exhaust,check or change the impeller on the pump

[Neil]

Thanks guys,
Yes the belts are perfect. We found the charging problem, a batterie post connection arcked out. Must have been loose. Previous owner just did the pump impeller. My next thought was to go ahead and replace the pump, keep the old as a spare. We have been running her a lot. Keeping the RPMS below 2700 and she stays at 175 degrees no problem. We aren't in a rush to get anywhere, but I'd like to figure out why she is running hot.

[WillieC]

is your sender and/or temp gauge accurate? Mine was 50 F off in a much "repaired" A25.

[Neil]

50 degrees!!!!????!!!!
How does one go about testing the sender? The thermostat is new.
Thank you in advance!
Neil

[WillieC]

See my post in A25/27.
viewtopic.php?f=28&t=9324

Basically I pulled the sensor, heated it up in a pan of water with a fairly reliable pocket temp gauge and recorded resistance readings. Fortunately, I had another sensor that I was able to compare it to. My first clue that something was amiss was that the installed sensor didn't change resistance until I was at 150F. I also had a small selection of resistors that I used to test the accuracy of my gauge. The spare sender resistance readings made my gauge report quite accurately. Unfortunately, it had the wrong threads. For now I am simply adding 50F to my reading, i.e. I don't want to see much over 130F on my gauge.
I can dig up my resistance readings if that would help. Most manufacturer's will say to use their proprietary senders, but I am skeptical and my boat (and potentially dying engine) is 43 years old. I'm not looking for any warrantee, just want to know where I am.
The fact that your gauge is showing higher temp at greater load is a good sign. Pay attention to that. Some folks have had success with infrared heat sensing guns. The trick is to certify what is true and dependable so you can make informed decisions, like a lot of life.
Happy to help if I can. Rick (WillieC)

[Neil]

Holy Moley Rick!
You are obviously far more intelligent than me!
Thank you for the process, that's a big help. Good luck with your boat, I hope you get another 40!
Neil