I mean the valve under the engine for the water when the boat is in the water do I need it to be open or closed when I start the boat out of the water and I hook up a garden hose I open the valve and water comes out of the headers so when I'm at the river I would assume I should have the valve open for water flow is that right
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Gotcha.
Yes the valve would be partially open. If this is a gate valve the valve setting is quite important.
Since there is no water pressure when the motor is not running, you don't need to close the valve with the boat in the water.
If you do indeed have water injected headers with a Bassett type tee, here is a proven way to set up the water valve (this is for a gate valve).
Get the boat in the water and pull out of the way of people at the ramp, find a spot out of the way and start the boat with the valve about half open and run it at idle, there should be NO water coming out of the headers.
After a few minutes of running, start closing the valve slowly (about a half a turn at a time) until the water temp starts to rise (look for about 140-150*F at the most).
Once that has happened, take her out for a cruise and watch the headers for steam, they should begin to steam at 1500-1800 RPM. If they come in too early (below 1500) you need to pinch down just a smidge on the valve (careful, those headers will be hot as hell). If they come in too late (above about 1800) you need a bit more water.
Your done. If something does not work the way you think it should, write it down.
Write down;
How many turns the valve is open/closed.
At what RPM the headers come in.
What the engine temp. is at idle.
What the engine temp. is at WOT and also cruise.
The temperature on the gauge might be all over the place for the most part. That is OK.
Figure about 150* at idle and probably about 120* or so at WOT. It can move pretty quick, so watch it for a minute or two before making any adjustments.
I keep my hand in the dump line stream when I am setting them up, but I have done over 100 of them.
Good hunting.
GT