17 to 19 pitch ? Pro - Cons

[dave524]

Hello. I have a 1996 Johnson 88SPL and it currently has a 17 pitch prop on it. I want to buy a spair prop, and am wondering will I get more performance with a stainless steel 17 pitch, or a aluminum 19 pitch. I am aware of the operating rpms and right now am in range with some to spare. Just lokiing for a little more punch. Also is waxing the underside of the boat a good idea ? As always, thanks in advance for reply posts.

 

[Dhadley]

Re: 17 to 19 pitch ? Pro - Cons

A lot depends on what brand & style 17 you have now and what brand & style you're switching to. Not all 17" pitch props - or 19s or 21s - are created equal. When you say you have rpm to spare - what does that mean? Needing more punch usually means going down in pitch.

Generally - very generally - speaking you'll get more performance with a ss prop because you can (generally) run the motor higher (less drag).

Start at the begining and tell us what your top rpm & speed is. Then what you're looking for. More top end or just more punch?

 

[dave524]

Re: 17 to 19 pitch ? Pro - Cons

hello again. I an running at 5200 rpm, with a 13.25 diam, 17 pitch aluminum prop. i can get about 40 mph out of it. I would like to change the prop to one that gets me up and on plane quicker, without so much bow rise. My dad doesnt like the feeling of looking at the sky when the boat goes up on plane. I did not think of going down in pitch, what should i do ?

 

[crb478]

Re: 17 to 19 pitch ? Pro - Cons

If you are only at 5200 rpm I would not go up to a 19. A good stainless 17 might get you 1 to 200 more rpm and have you closer to your upper target range. You could also drop to a 15 stainless and probably have a good hole shot but loose some on top end. If it is only the bow rise that is bothering you and you can not trim in enough to correct it then I would go to trim tabs. You can get smart tabs very reasonably priced or for a little more go with somethng like bennets.

 

[Dhadley]

Re: 17 to 19 pitch ? Pro - Cons

Sounds like we have some set up work to do with the prop you have. 5200 is lugging the motor. The first thing we need to do is get the rpm up without changing props. Then we'll need an accurate GPS speed to determine the % of slip.

Using the same prop and working the set up yu'll gain several things. The holeshot should be better, as the top rpms come up so will speed and it'll be much easier on the motor.

What kind of boat is it? Do you have a jackplate?

 

[dave524]

Re: 17 to 19 pitch ? Pro - Cons

The boat is a 1996 stratos 258, 16' and no it does not have a jack plate. it gets up on plane at about 25mph, and will cruise nice. Then you have about 1/4 throttle till it hits top end of about 45 mph. I want to say that when cruising at 25 and you nail it, this really puts you back in the seat. The boat has plenty of power, I just would like a little better hole shot.

 

[Dhadley]

Re: 17 to 19 pitch ? Pro - Cons

Generally speaking an aluminum prop doesn't like a lot of height but let's try raising the motor 1 hole and see how the hull responds. We're not looking for some huge improvement, just a sign that we're going in the right direction with this prop.

Is the prop vented?

 

[Randybeall]

Re: 17 to 19 pitch ? Pro - Cons

In answer to your last question, yes, a clean waxed hull will keep new boat performance qualities.
As to the prop questions, do you have power trim and do you use it for acceleration. Some boats will get on plane faster if you trim in before starting off and move it out while coming up to speed. Some boats have an almost critical trim position and are hard to get on plane until it is where the combination works best. I would suggest experimentation with trim angles. Raising the engine one hole as suggested would seem in order also. Before you spend money know that you have the best adjustment for the prop you have and the recomendation of prop size becomes much more accurate. The 19 would kill your launch and up to plane acceleration as things are now.

 

[Benny1963]

Re: 17 to 19 pitch ? Pro - Cons

man im sold put some smart tabs on it will plane faster ,run the prop ya have for know put a jackplate or go up a hole or to watch water pressure
then mabe you will be able to spin a taller prop .i got with hadley i have a mckee with 175 had bad bow lift prob and porping prob ,was running 21p
ss omc i installed tabs cut down on bow rise by 40 percent stoped the porping , installed jackplate and waterpressure gauge ,jacked it up till lost a little then back down 3/4 inch regained waterpressure .ran the 21pss ran 48 at 5800 but would pull higher went to turbo 1 three blade 22p
ran 56 gps at 5800 with a little left may have prop worked a little to take that little bit of rpm off ,between the tabs and the manual jackplate
its not the same boat ,its nasty know for a whaler style hull, hadley and gunner and these guys know whats up good luck,