Raw water cooling warmup time

[FYN409]

I have a 7.4 liter that is RWC. It appears that it uses a 140 deg thermostat. For those of you with a similar setup, how long does it typically take to get up to operating temperature? I start the boat and let it idle for about 5-10 minutes before departing, and typically if I stay in at no-wake speeds I have gone as long is 20-30 minutes before reaching operating temp. I am starting to think my thermostat is stuck open.

I am will probably replace the thermostat this fall when I winterize just in case, but was wondering what others have found with their warm-up times?

-Ryan

 

[Carpedmman]

20-30 Minutes seems like a very long time to me as well! My 454 Raw water cooled engines take about 10 minutes or so depending upon the temp of the river water.

 

[sbw1]

Agree, too long. My 370 had that set up. 10 minutes or so and we were at operating temp.

 

[FYN409]

That's what I thought. Sounds like I will be replacing the thermostat before re-commissioning this spring. Thanks for the info!

-Ryan

 

[Sundancer]

On the muffs, it takes 5 - 10 minutes to open the thermostats. At the dock, as soon as both engines will hold their own, we're off. I don't wait for the temp to come up before we leave the dock. That's typically a minute or less. The starboard engine is crankier and needs a little more time. I start it first, then start the port engine.