50 hp on a tracker PT165

[madhunter]

Hello all, I have finally got my 50 hp Johnson on my Bass tracker boat and now I need a prop. Funny thing is I do not have a prop on it. Does anyone have a suggestion for a good starting point. I am a college student and I can not afford to buy too many of these.

 

[madhunter]

Re: 50 hp on a tracker PT165

I can be more specific.

1999 Bass Tracker PT165
2005 Johnson 2 stroke 2 cylinder
2 people
11 gallon tank
100 - 150 pounds of gear

I "THINK" max rated RPM is 5500 but I may be wrong.

Thank you all

 

[Silvertip]

Re: 50 hp on a tracker PT165

12-1/4 x 15P cupped aluminum will work fine. Depending on the efficiency of the hull and whether the engine height is setup properly, you might be able to run a 11-3/4 x 17P cupped aluminum. But that engine will safely run (and likes to run in the 5800 rpm range so don't be afraid to let it spin that fast. The 12-1/4 x 15 is the most common prop for boats of that size.

 

[madhunter]

Re: 50 hp on a tracker PT165

12-1/4 x 15P cupped aluminum will work fine. Depending on the efficiency of the hull and whether the engine height is setup properly, you might be able to run a 11-3/4 x 17P cupped aluminum. But that engine will safely run (and likes to run in the 5800 rpm range so don't be afraid to let it spin that fast. The 12-1/4 x 15 is the most common prop for boats of that size.

Thanks. I will get a prop and go from there. I will report back.

 

[hwsiii]

Re: 50 hp on a tracker PT165

Mad,if that motor has a 2.42:1 gear ratio as I show, you will need a 17" pith prop.


H

 

[madhunter]

Re: 50 hp on a tracker PT165

Mad,if that motor has a 2.42:1 gear ratio as I show, you will need a 17" pith prop.


H

Thanks so much h and silver. I went to the prop shop yesterday and I took the motor info and the guys there helped out and we got a 11 3/4 x 17. Completely changed the performance of the boat. It still has a good hole shot and the top end is drastically improved. I have not had it out with the GPS yet but I am sure it as around 30mph. 5600 RPM max at WOT.

My only question is what difference would it make to run a 12 1/4 x 15. I realize that the shorter pitch would affect the top end but what would the larger diameter do?

Thanks a lot guys for the input. I appreciate the help.

 

[madhunter]

Re: 50 hp on a tracker PT165

Well just info for anyone interested.

I got it out with a GPS today and it ran maxed out at 34.0 mph @ 5600 rpm. And it cruised well at 25 mph. Again the hole shot was not the "cat on fire" that it had been but it is still very respectable.

Shawn

 

[hwsiii]

Re: 50 hp on a tracker PT165

Mad, your max RPM should be 5,500 so at 5,600 you are definitely running max RPM, and your prop slip is only 9% whih is exellent. Theoretially hanging to most 15" would let you over rev the motor about 800 RPM. I don't think that would be a good idea, if you want a "at on fire" holeshot buy a Solas Amita 4 blade prop in a 17" pith andyou should be turning about 5,300 RPM.


H

 

[madhunter]

Re: 50 hp on a tracker PT165

Mad, your max RPM should be 5,500 so at 5,600 you are definitely running max RPM, and your prop slip is only 9% whih is exellent. Theoretially hanging to most 15" would let you over rev the motor about 800 RPM. I don't think that would be a good idea, if you want a "at on fire" holeshot buy a Solas Amita 4 blade prop in a 17" pith andyou should be turning about 5,300 RPM.


H

Oh it has been a while. The prop I have is a 11 3/4" x 17P. That is giving me the specs I listed above. So what difference would the 4 blade give me over the 3 that I have on the boat now? Say to my top end?

 

[Silvertip]

Re: 50 hp on a tracker PT165

It should not affect top end. It raises engine rpm at all reference points. It will provide better hole shot. I've experimented with that engine on a couple of different boats and all of them performed best with a 12-1/4x15P. My testing included both cupped and uncupped. Keep in mind that all props are not created equal. A 15P from one manufacturer may not perform the same as a 15P a different manufacturer. Rake, amount of cupping, blade shape, etc. are all design factors.

 

[madhunter]

Re: 50 hp on a tracker PT165

I am not really looking for a better hole shot or more top end. Just want the best prop for the boat. With the 11 3/4" x 17P I am running at 5600 rpm W.O.T. so if I understand props right a 15P would increase rpm and I am sure that I do not want that. If anything would I not want to go up in pitch? And what difference does the extra 1/2" in diameter give me?

I sure appreciate the information guys, just having this information is invaluable.

 

[Silvertip]

Re: 50 hp on a tracker PT165

Two inches of pitch does not raise RPM 800 rpm. If you are currently running 5600 with the 17P a 15P of the same design from the same manufacturer would up the RPM by another 300 - 400 putting the engine at it's sweet spot of 5900 - 6000 (150 - 200 rpm/inch of pitch). Some engines simply love to rev a tad higher than the manufacturers upper limit and your engine is one of them. I personally owned one that was propped to run 5800 - 6000 and did so from the day it was purchased in 1995 until it was traded in 2004. Further, should you load heavier than normal at any time, you will appreciate the extra grunt. Since your engine is a two cylinder it will also troll better with less chance of load up and stalling because of the slightly higher trolling rpm. Prop selection is more than just running numbers through a calculator. That is a startng point but on-water testing is the way to optimize the setup. Which brings up another point. You may pick up some rpm and performance if you have not optimized the engine mounting height.

 

[madhunter]

Re: 50 hp on a tracker PT165

Two inches of pitch does not raise RPM 800 rpm. If you are currently running 5600 with the 17P a 15P of the same design from the same manufacturer would up the RPM by another 300 - 400 putting the engine at it's sweet spot of 5900 - 6000 (150 - 200 rpm/inch of pitch). Some engines simply love to rev a tad higher than the manufacturers upper limit and your engine is one of them. I personally owned one that was propped to run 5800 - 6000 and did so from the day it was purchased in 1995 until it was traded in 2004. Further, should you load heavier than normal at any time, you will appreciate the extra grunt. Since your engine is a two cylinder it will also troll better with less chance of load up and stalling because of the slightly higher trolling rpm. Prop selection is more than just running numbers through a calculator. That is a startng point but on-water testing is the way to optimize the setup. Which brings up another point. You may pick up some rpm and performance if you have not optimized the engine mounting height.

I was going to ask the question of height. I am currently sitting as low as possible. How do I go about deciding on height? just raise it to the next hole and give it a run? I have a set of hole that I can raise the motor to. I can take photos of the current placement to give an idea where i am now.

 

[Silvertip]

Re: 50 hp on a tracker PT165

The AV plate (plate just above the prop) should be even with or an inch or so above the bottom of the boat. This is a trial and error thing so before you make any adjustments, make some WOT GPS speed and careful RPM notations so get a good baseline, and by all means you need to use your trim control to get the best speed. Then move the motor up one hole and try again. I can almost assure you full down is not the best setting and yes -- pictures are helpful. Keep in mind you may only gain one or two MPH by optimizing but with that boat/engine configuration you might surprise yourself that this engine loves higher rpm.

 

[madhunter]

Re: 50 hp on a tracker PT165

The AV plate (plate just above the prop) should be even with or an inch or so above the bottom of the boat. This is a trial and error thing so before you make any adjustments, make some WOT GPS speed and careful RPM notations so get a good baseline, and by all means you need to use your trim control to get the best speed. Then move the motor up one hole and try again. I can almost assure you full down is not the best setting and yes -- pictures are helpful. Keep in mind you may only gain one or two MPH by optimizing but with that boat/engine configuration you might surprise yourself that this engine loves higher rpm.

It is dark right now, but in the next day or two I will get a picture or two.

Currently I am at the following:

1999 Bass Tracker 165
2005 hp Johnson
WOT: 5600 RPM
Speed 1: 34 MPH light load with only me
Speed 2: 32.5 MPH with 2 guys and gear.
Hole Shot: I would say 7 of 10. A little slower with a larger load but she still scoots.

Thanks for the info Silvertip, I can not wait to try another prop and see if the boat & motor perform better at another height. I am however not ashamed of what I have now though.

 

[Silvertip]

Re: 50 hp on a tracker PT165

You indicate 5600 rpm at WOT with a light load and you post speed with two aboard, but not the rpm. That would be nice to know as well. Just remember that what I said about all props not being equal. Unless you select a 15 prop from the same manufacturer and in the same model series as the 17 you may get very different results than you (or I) expect. Just because the prop is 15P does not mean all 15P props perform the same.

 

[madhunter]

Re: 50 hp on a tracker PT165

Silvertip, I am getting the boat back on the lake on Monday and I will get a little more information for specs with full load. And I will get pics of the motor height.

Thanks again