I picked up this boat this last weekend.  There are two regular lever valves one in the back by the Jet that controls the water intake for the engine.  One in front of the motor for controlling the water to the wet stacks.  The problem is I don't know exactly how to control them.  I was told too much water to the motor with the cam that is in it will cause water to back up in to the engine (bad).  The amount of the water going to the stacks will do the same if too much and blue the stacks if too little.

So my question is how does one solve these?  I could mount a remote valve near the driver for the water for the stacks and just shut it down or low at idle and open it at higher RPM's etc.  There has to be a easier way.

What is the procedure that I should be adjusting these valves by?

Is there another piece of hardware I can use to solve these issues?