My water temp gauge decreases as i increase boat speed.

[fixer.5]

I have a 2000 Four Winns 230 bow rider with 5.7 GSIl GM block. I changed the thermostat, and when on muffs, plenty of water came out the exhaust. The only thing I have not done is to change the water pump impeller. The only thing I can think of to cause this is water temp sending unit or water temp gauge. Anybody have any ideas.

Thanks Fixer.5

 

[Bondo]

Re: My water temp gauge decreases as i increase boat speed.

I have a 2000 Four Winns 230 bow rider with 5.7 GSIl GM block. I changed the thermostat, and when on muffs, plenty of water came out the exhaust. The only thing I have not done is to change the water pump impeller. The only thing I can think of to cause this is water temp sending unit or water temp gauge. Anybody have any ideas.

Thanks Fixer.5

Ayuh,.... Welcome Aboard,.... The Impeller is Always the 1st place to look in an Overheat situation....

 

[rickryder]

Re: My water temp gauge decreases as i increase boat speed.

Sounds like the T-stat is staying open if the temp DECREASES on acceleration.....Whats the temp at idle? What does it drop to when your cruising? It should stay around 160...

Bond-o is correct that you should look at your impeller if you don't know the condition of it.....pretty much a yearly thing.

 

[fishrdan]

Re: My water temp gauge decreases as i increase boat speed.

^^^ X3, replace the impeller

 

[fixer.5]

Re: My water temp gauge decreases as i increase boat speed.

Ayuh,.... Welcome Aboard,.... The Impeller is Always the 1st place to look in an Overheat situation....

Bond-0
Thank you for the quick reply. As soon as I can get the boat out of the boat shed,I'll replace the impeller.

Another post suggested the Thermostat could be stuck opened. I changed the T sat (160Degrees) and it read 160 at idle.
I'll let you know the results soon.
Thank's for the help Fixer.5

 

[rickryder]

Re: My water temp gauge decreases as i increase boat speed.

Bond-0
Thank you for the quick reply. As soon as I can get the boat out of the boat shed,I'll replace the impeller.

Another post suggested the Thermostat could be stuck opened. I changed the T sat (160Degrees) and it read 160 at idle.
I'll let you know the results soon.
Thank's for the help Fixer.5

What did the temp drop to while you were underway??? Just cuz the t-stat is new doesn't mean it's not faulty or something got stuck in it..... Your not overheating .....your over cooling which leads me to believe cold water is entering the block bypassing the t-stat....