SoCal Jet Boats

Tech Talk => Engine Mechanical / Electrical => Topic started by: newrob1 on February 24, 2014, 01:47:28 PM

Title: New here, please explain this.
Post by: newrob1 on February 24, 2014, 01:47:28 PM
I just got my first boat and got it running after sitting 10+ years.  My question regards plumbing.  The water intake hose from the transom to the engine came with 2 (assemblies).  1 is a simple T which I used to provide water to get engine running.  The other replaces the water inlet with a valve.  I will assume that this is used when boat goes in water so what is the technique used with the valve?  Thanks for your help, don't want to blow things up by not asking questions first.  No ego here...
Title: Re: New here, please explain this.
Post by: ka0tyk on February 24, 2014, 01:56:35 PM
the valve is used to regulate engine temperature.  keep an eye on your temp gauge while idling and adjust as necessary. 
Title: Re: New here, please explain this.
Post by: newrob1 on February 24, 2014, 02:11:03 PM
what am I targeting as a temp? 140-160?
Title: Re: New here, please explain this.
Post by: Havasukona455 on February 24, 2014, 03:46:18 PM
You want about 135 to 140 when cruising and about 180 when idling


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Title: Re: New here, please explain this.
Post by: Your Mom on February 24, 2014, 06:52:35 PM
What engine? BBC or BBO water temp/pressure is important to set...BBF not so much. I run my valve all the way open all the time with BBF. When I had an olds it was around 160-180 with just off plain/cruise spikes up to 200. Olds will crack in water jackets around valves with to much water.
Title: Re: New here, please explain this.
Post by: ka0tyk on February 24, 2014, 07:10:57 PM
Yeah it really depends on the motor and how it was built. Temp is important but not as much as oil temp.
Title: Re: New here, please explain this.
Post by: GT Jets on February 24, 2014, 07:30:41 PM
IMHO anything above 160*F is too hot.

Basically, depending on the total set up, with the boat idling at the dock, turn the valve toward closed at idle until the temperature starts to rise. I like to see about 155* at idle for a start.

As the engine speed increases the temperature should fall fairly quickly. On a Berkeley pump, the temp should be around 120-130* if everything is sized correctly.

Unless the engine has an automotive style water pump on the front, stay below 155*, there is NOTHING circulating the water within the cooling jackets on a jet. So 170*F at the gauge means that many areas in the block will be in excess of 220*...

GT
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