Re: how to get more speed out of a 15hp 4 stroke yamaha
OK; its very difficult to make any changes without some specs.You will need a tinytach for RPM,and a gps for speed.Tinytach is reasonable, easy to install and will fit any similar 4 stroke without regard to stator poles.In the mean time describe its performance,typical load,Hole shot,load pushing,approximate top speed.
The little 4 strokes require very careful setup need to run at max rpm.
Careful prop selection based on the present prop,max speed and rpm will help. You can raise the motor vertically 1/4" at a time by placing sticks on the top of the transom.Raise it to a point just before venting becomes a problem.just be sure it pumps water and has a good grip.careful trim selection.Could get you a little more speed and slightly quicker hole shot.Eliminate weight.plastic oars instead of wood,3 gal plastic tank instead of a steel 6,No unecessary items aboard.
light styrofoam cooler with cans no bottles.Less ice but shade the cooler.
Carefull weight placement.Once you have your specs prop selection should be easier.
