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Posts: 23
Location: Stewartville, MN | I was at Cabela's over the weekend and they had a SS Prop in their Bargin Cave for $200. It is a Cabela's High Performnace 13.25 x 15. I went looking for a 13.25 x 17 for my Yamaha 100 HP 4-stroke. The salesman said that by going SS I could drop down in pitch. I bought it, but have yet to install it. I wanted to check with the real "experts" on this board before proceeding.
FYI I have a 2000 Lund Angler 1700 SS with a 2001 Yamaha 100hp 4-stroke. I am not looking for top speeds, just a "good" prop.
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Posts: 190
| Watch out with that cabelas high proformance prop. It is heavily cupped which is good because it prevents slip, but it will drop your RPMs about 200-300. Each pitch will move your RPMS 200-300 hundren so by moving from a 15 to a 17 all thing being equal you will reduce your rpms by 500 - 600 hundred. Just make sure when you test it out that the motor can get to the required operating range. With the standard yamaha black stainless steel I can run a 19 pitch and keep my rmps in range, with that cabelas I had to drop down to a 17 because it is a great prop with no slip.
I have a 19 high proformace prop but I can't run it on my 17.5 boat with a 115, so with a 100 I would try the 15 pitch first.
my 2 cents.
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Posts: 144
| He is going to gain RPM by going to a 15 from a 17. If you had an aluminum prop before, your holeshot and overall performance should improve greatly. I don't have any expirience swithching from aluminum to stainless, but I would have gone with the same pitch for starters. I think pitch sizes for the most part go in odd numbers, at least in my expirience, so a 15 would actually only be one size down from a 17. What is the rpm range of your motor, and what are you getting with your current prop? |
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Posts: 3514
Location: Elk River, Minnesota | Hi,
Depending on where your RPM's are now, you may have the correct prop in hand. When switching from Aluminum to stainless, there is usually a drop in RPM's when you stay with the same pitch and diameter. The reason for this is due to a significantly less amount of blade flex as the prop turns in the water. In some cases, though ( and this is general and not a hard and fast rule here), the RPMs may not change due to the design of the prop. For example, the Yamaha aluminum prop and it's standard stock steel prop. They are identical except for their materials, so what one mainly gains from going to the steel equivalent is durability. Because the design is the same, the overall performance characteristics will be similar.
When you switch to an aftermarket prop, there are many other variables that come into the picture. Blade design, thickness, pitch, and diameter are different than what you have from the stock aluminum, and each characteristic will do different things for the rig. No matter what, there is a compromise in anything you do, but in many cases that compromise is minimal as compared to the gains you will see in other areas.
Because you are swtitching away from your standard prop and going to the cabelas prop, you are right in choosing a lower pitched prop. In most cases, going from stock to an aftermarket prop in the same pitch and diameter usually means a drop in RPM around 200 - 300 RPM (due to the lack of flex in steel and the extra cupping on the blades trailing edge) So...to get the equivalent RPMs to what you have currently, going down in pitch will be the correct move. The most common switch is to go down 2 inches in pitch when you switch from aluminum to steel. (again, not a hard and fast rule, but generally the norm)
Now..in your case, going down to a 15 pitch you will see the following: Increased hole shot...your boat will most likely jump up on plane much quicker than with your stock 17 pitch. You will also probably feel the boat being lifted a little more out of the water in the stern due to the cupping on the trailing edge of the prop. That increases lift overall, so you may also have to trim the motor up less for your desired setting. In turning, the prop will not "let loose" on a moderate turn as well.
What you may see as a compromise is a touch of top speed lost, but with less flex that could be negligible...all depends on what the prop does for you.. If your RPMs are a little low (like 250 or more) when you try the prop out, you can move the motor up a mounting hole and try again. you can gain some RPMs back in that manner, and with a switch to steel, the prop will usually keep a bite on the water well. That is the real difference in steel....it allows you to move your motor up to get more RPMs without much loss in handling...but it does have a limiting factor as well. It is also a test-and-see situation.
Now..if you decide you want to try more props, there are plenty out there that may even make the boat perform even better. But..that is a test, test, test again situation, and some don't like to do that...due to time, or just don't care for the 'putziness' of it. If you get the urge to do so, I have found the michigan ballistic to peform very well on different rigs with yamaha engines. I have a 90 2 stroke yamaha and turn a 17 pitch ballistic. It has the same RPM's as my stock aluminum 17 pitch (same as yours) but I saw increases in every area. I'm running a multispecies rig (alumacraft navigator console) and have the motor mounted in the highest possible bolt-hole position...and it still hooks up well. Top speed is just a touch below 40mph with my normal load.
Good luck and report back on how the change-over went..
Steve |
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Posts: 720
| Steve
Great post man you hit the nail right on the head. Your expierences and mine are exactly identicle to mine. |
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Location: Athens, Ohio | Only thing I can add is to be sure when you replace the prop to lube the shaft splines with teflon grease, and torque the prop nut to the proper pounds. good luck with it, m |
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Posts: 190
| Great point, what is the proper touque for a prop nut for a yamaha?
I'm not sure if I saw this in the manual
Thanks
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Posts: 3514
Location: Elk River, Minnesota | The service manual for my 90 yamaha shows 25 ft-lbs. I would wager a guess that your 100hp would be the same.
To me, I don't worry too much about it...Tighten it on, and once snug, adjust the castle nut by tightening further so that you can get the cotter pin through the shaft.
Steve |
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Posts: 375
Location: Browerville, Minnesota | So let me throw this out then. I bought a SS from Cabela's as well. With my factory prop on my 90 Optimax, I was hitting right around 5500 rpms. Max for the motor is 5700 if I remember correctly. Since I was close to the peak RPM's, I bought the same pitch prop. Now I won't know exactly how it is going to run until I get it on the water, but what are your feelings as to what it will do to my performance. I was hitting about 43 mph on the GPS with factory prop. |
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Posts: 3514
Location: Elk River, Minnesota | If the diameter is the same (I'm guessing it will be within 1/4" of your stock prop) I would think you will see a drop in RPM...but...that all depends on what the prop does for the boat. My gut instinct tells me you will see a drop in RPM of some sort, but you may be able to gain some of that back by raising your motor off the transom, which you should have NO problem doing. I'd maybe start 3 holes up and test there. Raising 3 holes up should give you around 250 or so RPM's upward, and if you see a drop in RPM from the change to stainless, you'd be awfully close to your RPM's currently. If (and this is a big if...) you are successful with a motor height change and going stainless, you should see an overall increase in speed, maybe an increase in hole shot, and definitely better handling and NOT having to trim down anywhere near as much for a moderate turn.
Cannot hurt to try...
If the cabelas prop does not work out, I would highly recommend trying a michigan ballistic...When I changed to that prop, I didn't lose any RPM's at all when I switched from my stock aluminum... But...as with any prop change, testing multiple props is the best possible determinant for finding the correct prop...nothing replaces testing...
Steve |
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Posts: 375
Location: Browerville, Minnesota | Thanks for the input VMS. Now ya got me to thinking. The reason that I stayed with the same prop pitch when I bought the stainless prop was because I went to the Mercury webiste and used their prop selector. It recommended that I stay with the same pitch for "overall good performance" and stated that if I wanted just more top end to go down in pitch. Will have to get it out on the water (if the lakes ever open up) and see how it does. If the performance isn't there, I will send the prop back to Cabela's and get an lower pitched prop. |
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Posts: 23
Location: Stewartville, MN | I made the switch the boat handles well, but I think I need to raise the motor and the WOT is in the lower side of the range. How hard is it to raise the motor? and how does one go about raising a motor? Is this something that can be done in a garage?
THANKS |
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Posts: 3514
Location: Elk River, Minnesota | Hiya,
If you are doing it yourself, all you need is the boat on the trailer with a tongue jack, silicone, and possibly a couple blocks of wood.
Here is what you can do...
1. lower the tongue jack to it's lowest position. adjust the outboard so that it is vertical to the ground. place blocks under the skeg. Attach and tighten your transom straps from the boat to the trailer.
2. remove the upper mounting bolts and only loosen the lower mounting bolts. (the lower bolts I would assume pass through a slot rather than an actual hole in the motor)
3. Now....go to the tongue jack and start cranking the tongue upward. you may find as you do this, you will have to go to the back of the boat to get the old silicone to "let go" so the motor will move on the transom. Once it does, you can continue to crank the tongue up until the upper mounting bolt holes line up on the motor.
4. Reinstall the upper mounting bolts using silicone as needed around the hole and the threads to seal the transom. Re-silicone the lower mounting bolts, and tighten.
5. Give the silicone some time to set up and go test...
Once you do it once, you'll have no issue readjusting as you feel you want to.
Steve |
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Posts: 95
Location: LOTW every chance I get | Thanks for all the great info on this topic Steve. Very helpful.
Dave |
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Posts: 622
Location: Seymour, WI | Hello Steve,
Can you please recommend a new prop for me?
I'm running a 2001 1750 Fishhawk with a 2001 Yamaha F 80 motor. The current prop is an aluminum 13.25 X 17 - K.
I currently get about 34 mph at WOT. I want to replace the prop because it's dented and dinged.
I'm just looking for a good all around prop for my set up.
Thanks,
Chris Grassel
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Posts: 3514
Location: Elk River, Minnesota | If you like the performance of your rig as it stands, I'd suggest staying with what you have. If you want to change but stay aluminum, you can check out a solas alcup 3, which will have a larger exhaust opening, but a fully cupped blade. It has a squeeze cast design so it will flex less than a normal cast aluminum, and with the cupping, will potentially get you a better bite on the water. The blades are a little bigger too, which means better thrust.
If you go steel, the michigan ballistic 13-5/8 x 17 should run the same rpm's as your stock aluminum, but it will allow you to move your motor up off the transom. I'm guessing your boat is a tiller model?
Steve |
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Posts: 622
Location: Seymour, WI | So I bought a MI Ballistic SS prop 13-1/2 x 17.
It dropped my rpm's by about 400, and dropped my top end speed by about 1-2 mph. The boat does not handle nearly as well as it did with my aluminum 13-1/4 x 17.
I'm running a 2001 1750 fishhawk console with a 2001 Yamaha F 80.
Do I need to drop down in pitch to a 15 or am I just better off with my old aluminum prop?
Thanks, Grass
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Posts: 3514
Location: Elk River, Minnesota | Hi Grass,
Before going to a 15, may I ask some information of your rig's set up? First and foremost is the motor mounted in the lowest position where it is snug to the top of the transom or has it been mounted up one bolt hole? If it is flush mounted, and you would be up to it, you could move that motor up so that the motor is in the highest bolted position off the transom. That would give you about 300 of those RPM's back. The bow may not rise as much as you accelerate too, which is nice. Just something to try if you are up to .
Otherwise, going to a 15 pitch prop might work too, and you may see similar performance to your stock 17 aluminum. That is the hard part about finding a prop that best suits a rig...it's test, test, and test more until you find one that does what you are looking for. When you find it, it's like that perfect shot in golf where the hit just feels like butter...
Primarily when changing props, especially in the lower HP range, what you gain is durability more than anything.....I'm right on that cusp too with mine. You might be right there too... All you can do is try. Keep me posted, I'll keep responding. I love this kind of stuff...
Steve |
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Posts: 622
Location: Seymour, WI | Steve, Thanks for helping me with this.
My motor is not flush to the transom, it is up 1 hole. There are four total holes, so I could move it up 2 more holes if you think that would help.
Also, Why does moving the motor up increase the rpms? Is it because there is less drag in the water?
Thanks, Chris |
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Posts: 3514
Location: Elk River, Minnesota | Exactly!! The leg of your motor acts much the same way as if you were to try and hold your arm upright out the window while driving 60 mph...it is very hard to do. So...by shortening the amount of leg that is submerged in the water, your motor will work less to keep the boat moving. As with any prop/motor height change, there is a limit to what you can physically get the boat to do, and the ultimate goal is to find the best possible combination for your type of running. The main trade off by going up with the motor is usually handling, but if you stay within the bolt holes on the motor, and staying stainless, you should not lose too much in handling. The higher you go with the motor, the less the prop will be able to hold the water, but steel props negate that. If you tried going up using your aluminum prop, it would would not do very well.
Never hurts to try moving the motor up and testing....if it doesn't work out, then move it down a hole and try again..
keep working on it...you'll find the sweet spot...
Steve |
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Posts: 622
Location: Seymour, WI | The boat does not handle very well now with the new prop in the 2nd hole so I'm worried that moving up to the 3rd or 4th hole will make it worse.
Chris |
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Posts: 3514
Location: Elk River, Minnesota | What is it doing? Can you elaborate on what the boat is doing? |
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Posts: 622
Location: Seymour, WI | I know this isn't the technical term for it, but the boat does not "turn" well with the new prop. The boat feels like it is skidding instead of turning.
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Posts: 3514
Location: Elk River, Minnesota | I have felt that before too...I assume you are trimming down in turns as well? If not, that could be part of the issue. What are your RPM's doing when you make a turn? Are they going up? If they are, the prop is ventilating on the turn, which (to me) would be one of two things: Motor trimmed up too high while turning, or the motor is mounted too far up on the transom. Seeing as though you are switching from an aluminum, being too high on the transom does not sound like the issue.
Now...I know my boat will do the same thing when I am not at high throttle settings...I get into a turn, and the prop will let go, but I don't feel the whole boat skid sideways, though. I have felt that, and it is definitely a wierd sensation.
Not sure what to say here, but if you are up to it, raise the motor off the transom and test it. If it gets worse, then I think the prop choice does not fit your boat. But...you may find it gets better.
How is the torque in the steering wheel? Oh...and where is the torque tab? That may need a little adjustment as well, which might explain some things too..
Steve |
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Posts: 622
Location: Seymour, WI | I don't think the prop I bought is the right one for my boat.
I'm going to look for an original Yamaha black ss prop. I'll let you know how it turns out. I put it up for sale in the buy/ sell forum.
You can see it here http://muskie.outdoorsfirst.com/board/forums/thread-view.asp?tid=44...
Thanks,
Grass |
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