Porpoising Issue

[h20 addict]

Hey Guys,
I have a 06 901 CDX with 200 optimax with 10" fixed jack plate, in anything but
calm water I have to trim all way down to keep from porpoising on me. Flat water
no problem, trim up and run 60 mph. Can anybody help ?

 

[jerry shack]

Try lowering your jack plate 1/2" at a time and see if that helps. It sound like it's to high and also what type of prop?

 

[h20 addict]

hey Jerry, thanks for the reply, I was thinking it was too high, and I am running a tempest
plus 23 pitch

 

[jerry shack]

That prop is a surface piercing prop so it has a lot of bow lift and what type of jask plate is it who makes it. because some have a different degree of angle.

 

[h20 addict]

Jerry, thanks again for your input, the jack plate is a slide master as far as I can tell, not
many markings on plate, but it is fixed. If were to invest in an adjustable one, any one
come to your mind. Would have to be manual budget won't go for other

 

[jerry shack]

The one you have should be adjustable via a long adjustable rod in the center and also a bolt on both sides to loosen the 2 plates. if not sure send a pic of it.

 

[h20 addict]

The one you have should be adjustable via a long adjustable rod in the center and also a bolt on both sides to loosen the 2 plates. if not sure send a pic of it.

Jerry, thanks for your input, I lowered my motor to about 3" below pad, I think that helped
a good deal. Waster conditions not the best to really tell. My jack plate is not movable, I know
what you are talking about, with the rod in the middle, mine does not have such an animal.

 

[jerry shack]

The rule of thumb is for every 1" of setback go 1/2" up. So your jack plate has a 10" set back so you measure from the pad with a straight edge and measure from the bottom of the cavitation plate to the straight edge. That's a good starting point. You can get a adjustable jack plate for around 300-500 bucks depends on the set back