Prop pitch W/jack plate.

[jtmaxdad]

I have a 1994 Nitro 170TS with 115 Marnier/Mercury. When I bought it twenty years ago needed it go to a stainless prop
Do to the abuse my boat would probably endure. I broke a couple of aluminum props on my previous boat. The prop on the boat had no numbers or any markings on it. So I employed a "prop wizard" online. It said that I should use a 23 pitch. No way. Too deep. So I exchanged it for a 21, which I ran for years. No hole shot to speak of but top end was in the fiftys. But couldn't get much past four thousand rpm. So I was looking for a used 19, and found a 17. With that prop I had a much better hole shot and I could run sixty three hundred rpm, sounded great but I can barely get over forty mph. Now here is my question for you "Prop Wizards". I just installed a hydraulic jack plate with a six inch setback. I have not put it in the water yet. Should I leave the 17 pitch on it or put the 21 back on it? I can't afford a 19,because that is where I think I need to be.
Thank you
Jim T.

 

[Starbanker]

That's a problem, if you can't afford a 19. I would try out the 21 and begin trimming and raising the engine until I got some ventilation. Your engine rpm will go up and so will the speed to a point when the prop starts to lose too much bite. Your hole shot may still be a wash, you get a better trim angle with a 6 inch set back, but you just added a couple hundred pounds to the transom.

 

[jtmaxdad]

That's a problem, if you can't afford a 19. I would try out the 21 and begin trimming and raising the engine until I got some ventilation. Your engine rpm will go up and so will the speed to a point when the prop starts to lose too much bite. Your hole shot may still be a wash, you get a better trim angle with a 6 inch set back, but you just added a couple hundred pounds to the transom.

Thank you for the input, kinda thought that is where I am at. I never ran anything with a jack plate. I just know with that 17 running a blistering 43mph, I actually think I saw a guy in a jon boat with a 10 horse tiller pass me.
Easy enough to change. I think I'll try the 21 on bigger lakes and drop to the 17 on a lot of the smaller lakes I fish. And just maybe if I am good boy mama will let me get a 19 next year. (Just this month I have spent over $600 in parts alone). I receive social security retirement benefits, so now I have the time to fish, I just can't afford to. Been married 46 years, I would hate to have to choose between my wife and my Nitro.
I love my boat!