190 degrees too hot for QSC 8,3 540?

This topic has 4 replies, 2 voices, and was last updated 5 years ago by Ron Carter.

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June 10, 2018 at 2:10 pm #33321

Ron Carter
Participant
Vessel Name: Sedona
Engines: 6C8.3TA
Location: SW Florida

This is a single engine 2006 42′ Nordic Tug with the above single engine. 1450 hours since new. Aftercooler and all exchangers taken off boat and professionally cleaned in November 2016, Salt water environment in SW Florida. Bottom is cleaned monthly. Last clean 10 days ago.

Fuel on board is 525 gallons or about 3600 pounds. Fresh water on aboard is 175 gallons or about 1200 pounds.

I usually cruise at 1650 rpms at a temperature of 170 degrees. The engine is supposed to reach 2600 rpms and reached 2580 when I bought it last year. During sea trial fuel was only about 200 gallons and the water tank was empty. At WOT the boat got up on a plane and reached a speed of 18 kts. The engine temperature rose to 180 and held steady.

Today with this heavy fuel and water load plus four adults I could only get 2500 rpms, 15.9 knots and the temperature rose to 190 degrees and held steady.

Is 190 degrees too hot for a heavy boat that is probably over propped from the factory at the git go?
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June 13, 2018 at 2:56 pm #33458

Ron Carter
Participant
Vessel Name: Sedona
Engines: 6C8.3TA
Location: SW Florida

Took most of the overload off and got a good bottom clean from diver and she ran like a scalded dog at 182 degrees WOT on official pre-sale sea trial.

All is well.

June 11, 2018 at 9:24 am #33345

Ron Carter
Participant
Vessel Name: Sedona
Engines: 6C8.3TA
Location: SW Florida

Overloaded seems to be the key word here. We’ll see during coming sea trial. Adding to the overload is that I forgot to mention a 12.5′ RIB with a 30 HP outboard riding to top…that adds close to 600 pounds to the fuel and water weights.

June 10, 2018 at 4:54 pm #33325

Ron Carter
Participant
Vessel Name: Sedona
Engines: 6C8.3TA
Location: SW Florida

Tony,

I will always listen to the Guru!!

190 is not my operational temperature. My operational temperature is 170 degrees all day long. Nothing has changed as far as I know. Entire cooling system off in November 2016 and new impeller couple of weeks ago as part of annual service.

Today was a short run up in anticipation to a pre sale sea trial this coming Wednesday. I know that the surveyor is going to insist on a few minutes a WOT. I want to be able to say that 190 is OK under these circumstances… or say that I will fix whatever is wrong.

Since I have had the boat I have thought many times of taking out some pitch. Then, after I thought about it, I decided that I very rarely cruised at more than 1600 and the although it would run up to where you said it needs to be, I did not care about it for a tug. A sportfish, absolutely, l want the full turns, but this is not really a planning boat. That said, anything will plane if you throw enough HP at it.

June 10, 2018 at 2:52 pm #33322

Tony Athens
Moderator
Vessel Name: Local Banks
Engines: QSB 6.7 550 HP
Location: Oxnard, CA
Country: USA

Ron,

Too Hot is somewhat relative.. In your case, it’s relative to the past history of operation and obviously, something has changed…

1) Your engine is over propped , and has been since you bought it…….More now as it has got heavier———–Not less than 2 inches of pitch needs to be removed…..Making 2680 ( the governor break point) and making it easy loaded as you use the boat is the number you want to see..

2) As to getting to 190F when running at WOT.. How much time are you spending at WOT and being over loaded to boot? That’s where the issue really is….

190F in itself does not hurt the engine, but it’s your operational condition that is worry some and whether you are will to listen to me..

SW Florida? Water temps as still cool compared to where they will be in Aug/Sept.. You need to think ahead

Tony
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