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Changed out my SS prop on 75opti back to the original aluminum prop for a trip I knew I would be make a lot of long runs.  My SS prop redlines too easy and I have not been able to get up to top speed because of it. 

anyhow, my aluminum prop only gets to about 5200 but my god does my entire engine run so much better.  Out of the hole just a bit slower but smoother at top speeds and 100x better at idle. 

I think I may be selling my SS prop and see if I can pitch up to get RPMs lower or just sell it and get a different aluminum prop that will run at higher rpm's than what I am getting now.  Goal is 5500-5600 I believe.

any "high performance" aluminum props I should be looking at that run well on these lower HP engines?

 

 

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I've been very happy with the Mercury "Spitfire" series... it's sort of an aluminum four-blade chop prop.

Tight lines,

Bob

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Before you make any changes check with a local prop shop to see if they can modify the one you have. Or they could supply you with one that better suits your needs. It may be a lot cheaper.  I am confused you say you are redlining with the ss prop. You say it only gets to 5200. You say your goal is 5500 to 5600. If the wot is the correct rpm when yo are properly trimmed out then your prop has too much pitch. The rough formula is if you add 1 inch of pitch then the rpm will drop 200 RPM. If you are too low now then you would need to drop pitch to gain rpm. I would verify my numbers with the ss prop. Then find a local prop shop.  They will help you get set up right.   

As for running a spare performance aluminum I can highly recommend just one and that is the Turning point Hustler. It is a true performance prop from the tuned barrel to the open tuned exhaust ports. I run one and love it.  West Marine and others sell them.  Just go to Turning Point's website and use their prop wizard. Also if you modify or replace your ss prop you still may want one of these for a spare like making special trips.  These props only cost about $120 and a Turning Point hub( model 502) will run about  $50. The Hustler can run a Merc hub but I recommend the Turning Point one so all you need to do is swap it out quickly.

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It's not what the prop is made out of, it's the pitch of the props that's causing you problems.

The only place I run aluminum is in Canada where a rock strike in unfamiliar water is a possibility.

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14 hours ago, fishnkamp said:

Before you make any changes check with a local prop shop to see if they can modify the one you have. Or they could supply you with one that better suits your needs. It may be a lot cheaper.  I am confused you say you are redlining with the ss prop. You say it only gets to 5200. You say your goal is 5500 to 5600. If the wot is the correct rpm when yo are properly trimmed out then your prop has too much pitch. The rough formula is if you add 1 inch of pitch then the rpm will drop 200 RPM. If you are too low now then you would need to drop pitch to gain rpm. I would verify my numbers with the ss prop. Then find a local prop shop.  They will help you get set up right.   

As for running a spare performance aluminum I can highly recommend just one and that is the Turning point Hustler. It is a true performance prop from the tuned barrel to the open tuned exhaust ports. I run one and love it.  West Marine and others sell them.  Just go to Turning Point's website and use their prop wizard. Also if you modify or replace your ss prop you still may want one of these for a spare like making special trips.  These props only cost about $120 and a Turning Point hub( model 502) will run about  $50. The Hustler can run a Merc hub but I recommend the Turning Point one so all you need to do is swap it out quickly.

Sorry...I corrected above.  My aluminum prop only turns 5200 and redline is closer to 5600.  My ss prop could go above 6000 as I have had it to around 5800 with throttle left.  Turning 5600 with SS my speed is about 1-2 mph less than turning 5200 aluminum prop does...and ss runs a lot more rough on it as well.

I have been thinking I need to pitch up on the SS prop to get more out of it however no local prop shops in the area for me to really try out...and when I ordered this a couple years ago I was hoping it would work well. 

I may not do anything at all as the boat is 6 years old and I may have the ecu chip flashed and if I do that I would need a much higher pitch prop for the 115hp range.

I will take a look at the aluminum props you recommend. 

Honestly, I just don't think these lower hp engines turn SS all that well.

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High performance and aluminum don't really go together. Sure there are some better than others, but stainless will always provide a better grip, better holeshot, and better top end as long as you actually have the correct prop. Your issue here isn't stainless vs. aluminum, it's more about two props that aren't the right prop for your setup and you like how one runs better.

My advice is to find the correct stainless prop for your rig to give you the best performance. Before you go looking, you'll need to decide on your performance goals. If top end is your end goal, then you will sacrifice some holeshot and vise versa. Do some research and put in some time. Go to a marine dealership and take a look at their props. Many have an abundance of used props that others bought and found out weren't right for their setup, much like you did. Most dealerships will allow you to try these out to see if they're the right fit for you. Some will have new props you can try too. When testing, have your boat loaded how you normally would on a fishing trip. If you normally fish with a buddy, then get one to go out and test props with you. If you take your time and find the right prop, there's no doubt you'll be happy with it.

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If your engine runs rough, particularly at idle with the SS prop, I'd hazard a guess that the prop is out of balance with a bent blade(s).  It's not necessarily something you could see by a visual examination,  It would have to be checked on a pitch block.

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1 hour ago, Nice_Bass said:

Sorry...I corrected above.  My aluminum prop only turns 5200 and redline is closer to 5600.  My ss prop could go above 6000 as I have had it to around 5800 with throttle left.  Turning 5600 with SS my speed is about 1-2 mph less than turning 5200 aluminum prop does...and ss runs a lot more rough on it as well.

I have been thinking I need to pitch up on the SS prop to get more out of it however no local prop shops in the area for me to really try out...and when I ordered this a couple years ago I was hoping it would work well. 

I may not do anything at all as the boat is 6 years old and I may have the ecu chip flashed and if I do that I would need a much higher pitch prop for the 115hp range.

I will take a look at the aluminum props you recommend. 

Honestly, I just don't think these lower hp engines turn SS all that well.

I'm sure you're aware you can't just slap on any prop and expect identical results as your other. Your issue isn't SS vs Alum. You have the wrong SS prop for your boat/engine and possibly an unbalanced SS prop.  A 115hp or 75hp (i'm not sure what you have as you reference both) can and does turn a SS prop very, very well. This is a pretty simple problem. If you want to run the SS prop, find what pitch it is and go up or down based on the specifications you want. If you don't want to do that, use the alum and sell the SS. 

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When evaluating a prop's performance, use a prop slip calculator.  Don't guess.  Get accurate numbers, plug them into the tool.

Here's two:

http://www.mercuryracing.com/prop-slip-calculator/

http://www.go-fast.com/Prop_Slip_Calculator.htm

Here is a good explanation of prop slip:

http://www.go-fast.com/prop_slip.htm

Every hull and setup is different, but my 18' Xpress/115 Merc ELPTO ran great with a 22p Laser II SS prop. Ran around 50 with a full load.

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1 hour ago, WIGuide said:

High performance and aluminum don't really go together. Sure there are some better than others, but stainless will always provide a better grip, better holeshot, and better top end as long as you actually have the correct prop. Your issue here isn't stainless vs. aluminum, it's more about two props that aren't the right prop for your setup and you like how one runs better.

My advice is to find the correct stainless prop for your rig to give you the best performance. Before you go looking, you'll need to decide on your performance goals. If top end is your end goal, then you will sacrifice some holeshot and vise versa. Do some research and put in some time. Go to a marine dealership and take a look at their props. Many have an abundance of used props that others bought and found out weren't right for their setup, much like you did. Most dealerships will allow you to try these out to see if they're the right fit for you. Some will have new props you can try too. When testing, have your boat loaded how you normally would on a fishing trip. If you normally fish with a buddy, then get one to go out and test props with you. If you take your time and find the right prop, there's no doubt you'll be happy with it.

Odd thing is it is the correct prop for the boat and engine and going up to a 21 pitch I believe will be too much with prop slip almost at 18% and 19 sits at 8%.  Alum prop is an 18 pitch.

I will say...I run a tracker 175 so I will never be the fastest boat on the water or high performance...just looking for a good ride at this point until the new boat is picked out in about another 5 years or so.  

38 minutes ago, Fishing Rhino said:

If your engine runs rough, particularly at idle with the SS prop, I'd hazard a guess that the prop is out of balance with a bent blade(s).  It's not necessarily something you could see by a visual examination,  It would have to be checked on a pitch block.

I am actually thinking it could be a difference in the hubs as I have two different versions and I somewhat recall reading years ago one may carry more vibration reduction than another.

37 minutes ago, iabass8 said:

I'm sure you're aware you can't just slap on any prop and expect identical results as your other. Your issue isn't SS vs Alum. You have the wrong SS prop for your boat/engine and possibly an unbalanced SS prop.  A 115hp or 75hp (i'm not sure what you have as you reference both) can and does turn a SS prop very, very well. This is a pretty simple problem. If you want to run the SS prop, find what pitch it is and go up or down based on the specifications you want. If you don't want to do that, use the alum and sell the SS. 

I don't expect that lol...that being said, may be a hub, or may be wrong prop but 21 pitch too much.  I do have a 75hp but may have the ecu flashed this winter to a 115 which will put the pitch closer to 23 or 25 I believe.

29 minutes ago, J Francho said:

When evaluating a prop's performance, use a prop slip calculator.  Don't guess.  Get accurate numbers, plug them into the tool.

Here's two:

http://www.mercuryracing.com/prop-slip-calculator/

http://www.go-fast.com/Prop_Slip_Calculator.htm

Here is a good explanation of prop slip:

http://www.go-fast.com/prop_slip.htm

Every hull and setup is different, but my 18' Xpress/115 Merc ELPTO ran great with a 22p Laser II SS prop. Ran around 50 with a full load.

8% by my math anyhow and seems like it is right in range.  May need to find a 20p if it is out there.  I have a laser II as well in 19 on 75hp. 40.2mph

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I wouldn't expect you could go much over a 22p, even with 115.  For comparison, I use a cupped 25 (makes it a 26) on a souped up 2.5L Pro Max Sport, powering a hull that is a few hundred pounds lighter than the Xpress, a Bullet 21XDC.  When I put a cupped 27 on that boat, the difference was noticeable.  Hole shot took forever, and top speed (within my driving ability) went up 8 mph.  They were same prop model.

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58 minutes ago, Nice_Bass said:

Odd thing is it is the correct prop for the boat and engine and going up to a 21 pitch I believe will be too much with prop slip almost at 18% and 19 sits at 8%.  Alum prop is an 18 pitch.

I will say...I run a tracker 175 so I will never be the fastest boat on the water or high performance...just looking for a good ride at this point until the new boat is picked out in about another 5 years or so.  

Why do you believe that's too big? If that's where you sit RPM wise the only way to know is to try it.

 

8 minutes ago, J Francho said:

I wouldn't expect you could go much over a 22p, even with 115.  For comparison, I use a cupped 25 (makes it a 26) on a souped up 2.5L Pro Max Sport, powering a hull that is a few hundred pounds lighter than the Xpress, a Bullet 21XDC.  When I put a cupped 27 on that boat, the difference was noticeable.  Hole shot took forever, and top speed (within my driving ability) went up 8 mph.  They were same prop model.

It really depends on what gear ratio lu he has. I'm not sure how much the mercury ones vary, but I know I was at a tourney with my old 88 hp Johnson that ran a 20 pitch Raker and solo would turn a 22 Pitch Raker pretty well. Anyway, there was a guy at a tournament who had a 150 Johnson on a bigger boat was running a 19 pitch. Same comparison with my 130 running a 24 pitch and my dad's 225 running a 25. Those are two different brands, but it really depends on gear ratio as to what prop you turn. 

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Just now, WIGuide said:

Why do you believe that's too big? If that's where you sit RPM wise the only way to know is to try it.

 

3 minutes ago, WIGuide said:

It really depends on what gear ratio lu he has.

That's true, but a 25 (mentioned earlier) sounds unrealistic to me. 

Gear ratio is a constant.  You can't compare different boats, different motors, and different gear ratios.  There are way too many variables, such as hull weight, hull design, He plugged his numbers into the slip calc, and 20 sounds about right. 

I used my bigger boat as a comparison to demonstrate how finicky the process can be.  Everything the same, except went up two inches on the prop, and the difference was pretty dramatic.

Anyway, sounds like a 20 is the right prop, in the same model.

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Aluminum and performance are not two words that go together when talking props. 

To be able to really tell what any prop is going to do you MUST have a good base line speed and RPM from a known good prop first, basically a brand new prop.  Once a prop has been run for a while, and especially if they were prop that came with a used boat, or bought used, you don't have a clue as the what damage they may have.  I've seen bunches of props that looked great or even like new that were trash and needed work because of edges being rolled or other damage the eye can't see.

As for sending an aluminum prop in just to have special work done, for me, that will never happen.  If I did happen to have one and it need to go in for repair  I might have the pitch tuned a little or a little more cup if I felt it needed it.  Shoot, don't know why I'm even saying that, if it's an aluminum prop, I throw it in the trash or give it away, don't care if it's good or bad.  I guess they do make OK spare props because they are lighter, if you are concerned about weight, but I even use SS props for spares. 

If you are serious about wanting to buy a new prop, a lot of dealers will let you try before you buy.  In other words, you want a new Raker prop, but not sure of the pitch, they will let you try one that should work, but if it's too much or too little, you can swap it for a different pitch that works better.   Not many are going to let you just start tying props and then walk out the door and just say thank you, so you can order it cheaper on the internet. 

If you are wanting peak performance from a prop, there are not many out of the box props going to give you that on any boat.  You get one that performs good and then send them to a good tuner with the data he needs to make it do what the boat needs.  Some boats need aft lift, some need bow lift, some need both, and some, like a Tracker tin can, would be kinda dump to waste the money.

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Here I have a contact for a fantastic prop shop in Tennessee get the model numbers off both of the props together.  Give them a call and discuss what you have what is doing and  he will fix you up. Call Dans Prop Shop  He deals with new and used propellers as well as custom work. 423 3332 9002 or www.danspropshop.com toll free877-332-9002

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10 hours ago, WIGuide said:

High performance and aluminum don't really go together. Sure there are some better than others, but stainless will always provide a better grip, better holeshot, and better top end as long as you actually have the correct prop. Your issue here isn't stainless vs. aluminum, it's more about two props that aren't the right prop for your setup and you like how one runs better.

My advice is to find the correct stainless prop for your rig to give you the best performance. Before you go looking, you'll need to decide on your performance goals. If top end is your end goal, then you will sacrifice some holeshot and vise versa. Do some research and put in some time. Go to a marine dealership and take a look at their props. Many have an abundance of used props that others bought and found out weren't right for their setup, much like you did. Most dealerships will allow you to try these out to see if they're the right fit for you. Some will have new props you can try too. When testing, have your boat loaded how you normally would on a fishing trip. If you normally fish with a buddy, then get one to go out and test props with you. If you take your time and find the right prop, there's no doubt you'll be happy with it.

That's it, right there.

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