Evinrude e-tec or Yamaha 4 Stroke

[walleyehed]

Re: Evinrude e-tec or Yamaha 4 Stroke

John, bottom line here is the figures given by Bombardier are not even possible in theory....Their numbers indicate a speed at X-RPM, with X-prop that is not possible. I have figured 1 in particular using a 17" pitch prop, and have found the speeds they show to be impossible...negative slip, no way, can't be done.<br />I THINK this is what the arguement is about, and I have to agree with forktail, as I have no idea where Bombardier is coming up with these numbers??????

 

[seahorse5]

Re: Evinrude e-tec or Yamaha 4 Stroke

Forktail,<br /><br />You are starting to sound like a political figure, expounding two different conflicting statements.<br /><br />Back in an earlier post on , you said "Cupping adds performance with some hulls, and subtracts performance with others. It has no effect on pitch." That is correct. But just now you said "If you modify an original prop by adding cup, it will change the original pitch", which is incorrect. As you stated in another post, pitch is measured in inches and a cup does not change the theoretical distance a prop will travel thru a solid object.<br /><br />Cupping, for the most part, enhances the performance of a prop, making it more efficient. Since it adds "load" to the motor, the rule of thumb is that is reduces rpm by about 150rpm for a normal cupping. Double and even triple cupping changes the equation even more.<br /><br />Since on most boats cupping changes the speed potential over no cupping, the pitch of the prop is still the same, but it performs as if additional pitch is added. For that reason, and as in a previous post by me, in speed calculations, you add about 1" of pitch to the formula to compensate for the increased efficiency. Sea trials show that the 1" "finagle factor" for cupping is pretty accurate on recreational boats.

 

[jegervais]

Re: Evinrude e-tec or Yamaha 4 Stroke

Kennyb,<br /><br />No arguement, just a friendly debate over a difference in opinion. I believe the moderator would have locked this thread if it was truly an arguement.<br /><br />

Yes, Perry. That is correct.<br /><br />If you modify an original prop by adding cup, it will change the original pitch. The original pitch includes whatever cupping originally came with the prop. It's in there.

Now all of a sudden you agree with us - as seahorse stated, he attempted to make that point some time ago. However, what you probably don't realize, regarding the OMC/Bombardier props - "the original pitch includes whatever cupping..." They do not follow this rule in two prop lines, the SST and the Viper - it's been in their P&A and prop info for years (the oldest catalog I have goes back to 1993).<br /><br />

6%-10% slip is very common. So that sounds right. The 3% negative slip would indicate a modified prop, or a prop that has been modified to a pitch greater than what is stamped on it. Theoretically negative slip can't exist because you can't get better traction than perfect traction.

6% to 10% yep, I agree. Negative % slip? Hmmm I never thought of it in those terms before. Interesting. Theoretically can't exist... Ok, I agree with that thought, however in practical application (consider the modified prop, ok) isn't that really what's going on? I'm interested in your explaination.<br /><br />

I assume the data comparison on the E-Tech was done with factory propping.

Your assumption is indeed correct, they did use stock, out of the box SST prop. And just to clarify, I never suggested they modified their prop. And to clarify further, when I talk about "tweaking" a set-up, I'm refering to the relationship of the motor to the boats' transom. I never did come right out with that, sorry for the confusion if it lead anyone to believe I was refering to the prop.<br /><br />Tweaking may include raising or lowering the mounting height of the engine and/or adding set back to change the balance point of the hull and achieve the performance gains of have less hull dragging in the water. <br /><br />For the record, there was zero set back used in any of the manufacturers tests which I quoted, however, all of them employed at least some engine mounting height changes.<br /><br />Forky I was wrong about you and apologize for calling you untrainable. But I have to ask, why were you being so stubborn?<br /><br />Regards,<br />John

 

[Forktail]

Re: Evinrude e-tec or Yamaha 4 Stroke

seahorse, my statements don't conflict, you just don't get it. <br /><br />My first statement relates to a stock prop, which when stamped with a 15 pitch, will include any cupping or other geometry of the blades. You can't take a stock cupped 15 pitch prop and say its a 16 pitch just because its cupped! If a stock 15 pitch prop is doing better than 15" per revolution, then it's not a 15 pitch prop!<br /><br />My second statement relates to a modified stock prop, where changes to the original geometry of the blades through additional cupping have changed the original stock 15 pitch. You can't take a stock 15 pitch prop and re-work the blade geometry and still call it a 15 pitch prop! Here's why...<br /><br />Double-cupping (modifying) a prop does more than just further curl the trailing edge of the blade outward. Double cupping begins to change the entire blade geometry further down the blade. The more cup you add, the more blade length is needed to do it.<br /><br />It's like trying to bend a curve in a flat piece of metal using your shop vise. You have to continually move the flat metal up and reclamp as you bend. Multiple bends along the flat give a better radial bend. It takes more length of the flat piece to do this. Otherwise you just get a 90 degree bend in one spot. <br /><br />If you still don't get it, just know this...double cupping usually ends up intersecting the original pitch lines, changing blade angle, and in effect increasing pitch.<br /><br />There is a huge difference in a prop originally designed with large amounts of cupping (double cupping), and one that is later modified with double cupping. Cupping has effects throughout the entire geometry of the blade, and thus the blade must be designed for the effects of that cupping. You can't really do this when modifying a stock prop, as the rest of the blade can not be changed to accomodate the new cupping. In other words double cupping can be designed into a prop for maximum effect. Where by modifying a stock prop afterwards, you only get what you get. <br /><br />

...in speed calculations, you add about 1" of pitch to the formula to compensate for the increased efficiency. Sea trials show that the 1" "finagle factor" for cupping is pretty accurate on recreational boats.

"Finagle factor"? So if we have a cupped 15 pitch prop, we can just call it a 16 pitch because it achieves less slip? NOT! All we can do is call it a more efficient 15 pitch prop! <br /><br />Lets use your theory....If we took a 15 pitch prop and added 1" of pitch for it's increased efficiency, we now have a 16 pitch prop. Right?<br /><br />Now we take that same prop off your boat and put it on a barge. Prop efficiency goes to hell. What do we do now?....call it a 2 pitch prop to get the speed calculations to work?<br /><br />It appears to me that, in both cases, the prop is still a 15 pitch prop. <br /><br />seahorse, you're trying to find a way to make that E-Tech data work by manipulating formulas and numbers, and by throwing physics and hydrodynamics out the window. If you want to justify it in your mind that way, go ahead.<br /><br />But if you honestly wanted to determine the fastest possible speed that a 15 pitch prop could obtain, you would have to call it a 15 pitch prop.

 

[jegervais]

Re: Evinrude e-tec or Yamaha 4 Stroke

 

[Forktail]

Re: Evinrude e-tec or Yamaha 4 Stroke

What's a matter John...did you hit a dead end? Couldn't show us how the E-Tech data works out, couldn't nit-pick my comments apart, and you're unwilling to admit the E-Tech data could be flawed. So you've resorted to posting ??<br /><br />

Now all of a sudden you agree with us - as seahorse stated, he attempted to make that point some time ago.

No, I don't agree with you and seahorse. Wishfull thinking perhaps. <br /><br />Read my last post above. There's a big difference in a stock cupped prop stamped with 15 pitch and a stock cupped prop stamped with 15 pitch, and then later modified some more. Get it?<br /><br />

However, what you probably don't realize, regarding the OMC/Bombardier props - "the original pitch includes whatever cupping..." They do not follow this rule in two prop lines, the SST and the Viper - it's been in their P&A and prop info for years (the oldest catalog I have goes back to 1993).

None of the E-Tech data listed here shows a SST or Viper prop. Are we changing the rules as we go along? Is that yet another "typo" too? <br /><br />If you're saying that the 15 pitch prop used on the E-Tech was not a 15 pitch prop, then you're saying what I've said all along. Go figure. Regardless, it's not even close, and it doesn't explain the same problem on the 40 hp data.<br /><br />

6% to 10% yep, I agree. Negative % slip? Hmmm I never thought of it in those terms before. Interesting. Theoretically can't exist... Ok, I agree with that thought, however in practical application (consider the modified prop, ok) isn't that really what's going on? I'm interested in your explaination.

"What's going on", is that the modified prop is no longer a 15 pitch prop, and therefore it is moving forward more than 15" per revolution. Is that so hard for you to comprehend? Or do you have some way of magically making a 15 pitch prop move more than 15" per revolution? <br /><br />Negative slip is not a term I like to use. It indicates wrong pitch, wrong speed, wrong rpm, or one hell of a tail wind. <br /><br />Go back up and review my screw example. The only way you could advance that screw into the wood more than one inch in 15 revolutions, is to force it, probably with a hammer. <br /><br />As for your "tweaking" comments, they really have nothing to do with the fact that you're trying to get a 15 pitch prop to magically move through the water more than 15" per revolution. Maybe you've got a hammer. <br /><br />

But I have to ask, why were you being so stubborn?

I'm not stubborn, I'm trying to help you understand....because I know what I'm talking about. I've been propping outboards, hanging out at the prop shop, and running calculations on prop setups probably since before you were born. As an engineer, I understand hydrodynamics.<br /><br />It is you John, who is stubborn and not realizing that the data on the E-Tech could be flawed. Nobody is blaming you for the data. However you have gone to great extents and thrown all priciples of propping out the window to defend the E-Tech data. Never once stopping to think that maybe there is an error, or a proper explanation. You've failed to show us how the data can possibly work.<br /><br />I find your comments about being "untrainable" and "close minded", along with your signature, ironic if not hypocritical.

 

[jegervais]

Re: Evinrude e-tec or Yamaha 4 Stroke

No that's not quite it. But dead end yes. The point regarding the "modified" prop as you call it, is what we've been trying to get across since the middle of page 2 of this thread. And I appreciate the fact you really do understand and recognize it.<br /><br />That you refuse to believe that's the way some marketing wiz-kid at OMC decided to do things probably 2 decades ago Well, ok. That's your prerogative...<br /><br />I've made my points, accurately I might add, and I realize short of parking your butt in that boat with one of "those" engines,nothing further is to be gained here. I'm confident, that we will eventually have the opportunity to say "Forky, we told you so." <br /><br />I'm sure you've done the things you've said. And, I know my accomplishments and appreciate the smiles I've put on the faces of all the boaters, both paying customers and internet aquaintances who I've had the pleasure of assisting.<br /><br />BTW, I was at least gracious enough to apologize for calling you "untrainable" or "closed-minded".<br /><br />Regarding my signature, I've found it to be true in life and especially so at times, with some boaters. I've had that signature for a long time - I didn't make it up special for this thread. At least I can say I stopped tangling with the fence a long, long time ago.<br /><br />Regards to all, this truly has been an "interesting" thread.<br /><br />-John

 

[Forktail]

Re: Evinrude e-tec or Yamaha 4 Stroke

 

[MurdockJr]

Re: Evinrude e-tec or Yamaha 4 Stroke

Don't you guys ever give up it's getting old!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

 

[Forktail]

Re: Evinrude e-tec or Yamaha 4 Stroke

John, read back. You've posted much misinformation throughout this thread. Now you're resorting to twisting words and using rhetoric to cover it up as you try to bow out gracefully (twice now). <br /><br />You are the "expert" who posted the E-Tech data, not me. And you've yet to show how that data can possibly be correct. All the propping banter in the world hasn't done that for you John. <br /><br />

The point regarding the "modified" prop as you call it, is what we've been trying to get across since the middle of page 2 of this thread. And I appreciate the fact you really do understand and recognize it.

In your dreams. <br /><br />My comments concerning "modified" props have to do with Perry's comment above about his local prop shop double-cupping props. I assumed he was talking about adding additional cup to his stock prop via his buddy at the prop shop.<br /><br />I said, "Yes, Perry. That is correct. If you modify an original prop by adding cup, it will change the original pitch." <br /><br />"Modified" means just that...a prop that has been changed from it's original condition. Perry said his 16 pitch prop had a "negative slip". If you would like to explain how a prop achieves "negative slip" without modification from its original pitch, I'm all ears. <br /><br />

That you refuse to believe that's the way some marketing wiz-kid at OMC decided to do things probably 2 decades ago Well, ok. That's your prerogative...

You appear to be saying that the 15 pitch prop used on the E-Tech was not a 15 pitch prop, due to marketing. If that is true then you have cemeted my point that your data did not jive.<br /><br /> <br />

I've made my points, accurately I might add

Again, you've posted much misinformation. Some of it is listed above in response to your "untrainable" post. I'll spare repeating it again here.<br /><br />John, outboard techs that really understand propping are very far and few between. Some, like yourself, know just enough to be dangerous, but not enough to be a know-it-all. And it seems so many techs these days are know-it-alls. <br /><br />

I realize short of parking your butt in that boat with one of "those" engines,nothing further is to be gained here.

Not until you prove your point with some facts. Rhetoric isn't going to cut it. Sorry.<br /><br />

I'm confident, that we will eventually have the opportunity to say "Forky, we told you so."

If you find a way to get a 15 pitch prop to move through the water more than 15" per revolution, you'll be rich and famous with one of the greatest inventions of all time. The laws of physics and the universe will have changed forever. "I told you so's to Forky" won't matter then. But I won't hold my breath.

 

[seahorse5]

Re: Evinrude e-tec or Yamaha 4 Stroke

Just came across this quote from the 90hp Suzuki spec site:<br /><br />"The 2.59:1 gear ratio is the lowest of any motor in this class and it allows the use of a bigger prop for slingshot acceleration and a faster top end.

 

[Tracy Coleman]

Re: Evinrude e-tec or Yamaha 4 Stroke

Anybody keeping up with this thread has got to wonder.... <br />

<br />There is a huge difference in a prop originally designed with large amounts of cupping (double cupping), and one that is later modified with double cupping. Cupping has effects throughout the entire geometry of the blade, and thus the blade must be designed for the effects of that cupping. You can't really do this when modifying a stock prop, as the rest of the blade can not be changed to accomodate the new cupping. In other words double cupping can be designed into a prop for maximum effect. Where by modifying a stock prop afterwards, you only get what you get. <br /><br />

Me thinks you give too much credit to what is possible, and less to what is. This is not meant to relate to the E-TEC test data discussion directly. A lot of props do not reflect actual pitch performance by what is stamped on the blade.<br />When the OMC SST props first came on the market, there was NO cup- none. This was in the 55 hp-115 hp "popular prop size" that Forky doesn't know exists,15,17,19,21. It wasn't long and they realized the need for a cup to pry the nose up on ill performing hulls, this was pre-power trim days-tilt pin only. Different geometry? No, same pitch block, same prop, one with cup, one without, same pitch number. Now that may disturb some people, but that is real world application back in the 1960's and is still around today. Is it a perfect example of the most efficent screw, no. A newer example would be Merc's 40, 50, 60 hp- aluminum p/n 48-42738A11 12 1/2 dia. X 8" pitch. Also available with (Extra Cup)-12 1/2 dia. X 8 pitch p/n 48-42738A13. Both the same pitch, blade area-difference in trailing edge cup. Different RPM, different speed, same pitch. As the Mercury Accessories Guide says for select props, "*Cupped Version Order CP1 in place of A45", A45 being uncuped models, otherwise same part number-different pitch load on the motor but stamped with the same pitch number. These are not completely different props arriving at the same pitch, they are the same prop, except for the last 1/4" of the trailing edge.Misrepresentation, can we allow this to stand?<br />"Where by modifying a stock prop afterwards, you only get what you get." <br />Like-What the hell does that mean? Many of the better prop people can adjust, modify a good prop to greatly out perform anything out of the box from the factories. Say like more stern lift, more bow lift,more pitch, less pitch, more rpm, less rpm, better handling, better hole shot, better top speed, cavitation control-"get what you get"- I had to laugh at that, sorry.<br />Fowlplay1-you get lost? God says to share!<br />Having more fun than a human being is allowed!<br />Backfire

 

[M13]

Re: Evinrude e-tec or Yamaha 4 Stroke

If anyone needs any technical information or a list of engine specifications about the E-tec engines they should call Bombardier's Consumer Support Line at 847-689-7090.

 

[seahorse5]

Re: Evinrude e-tec or Yamaha 4 Stroke

Backfire,<br /><br />Now its your turn to receive the ATTABOYS.<br /><br />I remember the original uncupped SST props when they first were introduced in 1973. They sold for the unheard of price of $79.95 while aluminum propellers went for $29.95. I bought a 17" for my new '73 85hp on a 16 Starcraft SS. Later when the cupped SST II came out, I was bummed until I found someone to buy my original version. The cupped SST allowed me to raise the motor a notch, gain a few mph's, and still pull slalom skiers up on one.

 

[butlp]

Re: Evinrude e-tec or Yamaha 4 Stroke

Backfire and Seahorse,<br />I suggest you go back to the beginning and read all the posts again. It is clear to me that both of you are very pro Bombardier and will defend them to the death and yet you have not answered Forktail’s argument that it is impossible for the E-Tech data to be correct if the prop used for the test had a 15 inch pitch.<br /><br />If manufactures in the 60, 70’s and even today make a non-cupped and double cupped props that are stamped with the same pitch, then one of the props is incorrectly stamped and IMO it is irrelevant to this discussion. It’s fine in the “Real World” for the average Joe looking for a new prop for his rig, but as a potential customer reading the data and specs of a product, I expect the manufacture to tell the truth. Therefore if the test is performed with modified, tweaked or double cupped prop then say so and don’t lie.

 

[Forktail]

Re: Evinrude e-tec or Yamaha 4 Stroke

Just came across this quote from the 90hp Suzuki spec site:<br /><br />"The 2.59:1 gear ratio is the lowest of any motor in this class and it allows the use of a bigger prop for slingshot acceleration and a faster top end.

Seahorse, maybe you could explain how this “best of both worlds” is possible? I’ll buy it that lower gearing and a bigger prop will give better holeshot...but faster top end too? We all know that higher gearing and smaller diameter props give more speed.<br /><br />You guys live and die by these sales pitches.

 

[Forktail]

Re: Evinrude e-tec or Yamaha 4 Stroke

Backfire, you continue to display your ignorance. <br /><br />

A lot of props do not reflect actual pitch performance by what is stamped on the blade.

Are you saying the 15 pitch prop shown on the E-Tech data was not really a 15 pitch prop? Gee, could this be related to what I’ve been saying all along?...that something doesn’t jive!<br /><br />So Mr. E-Tech man, then what pitch really is the E-Tech’s 15 pitch prop? And why would Bombardier come up with test data indicating a 15 pitch if it was something other than that? To make the comparison “look” fair against Yamaha’s 15 pitch? And what about the 40hp with that huge 17 pitch on it? It doesn’t jive either. So is it really a 19 pitch? On a 40 hp? Come on. You’re cracking me up here Backfire! <br /><br />

This was in the 55 hp-115 hp "popular prop size" that Forky doesn't know exists,15,17,19,21.

You said a 17 pitch was a “popular size” for a 40 hp. And you were wrong. Now you’re posting this crap, which only makes you look more desperate and ridiculous. <br /><br />

When the OMC SST props first came on the market

Since when did we start assuming the E-Tech data included a SST prop? No indication of that. <br /><br />

Different geometry? No, same pitch block, same prop, one with cup, one without, same pitch number. Now that may disturb some people, but that is real world application back in the 1960's and is still around today. Is it a perfect example of the most efficent screw, no. A newer example would be Merc's 40, 50, 60 hp- aluminum p/n 48-42738A11 12 1/2 dia. X 8" pitch. Also available with (Extra Cup)-12 1/2 dia. X 8 pitch p/n 48-42738A13. Both the same pitch, blade area-difference in trailing edge cup. Different RPM, different speed, same pitch. As the Mercury Accessories Guide says for select props, "*Cupped Version Order CP1 in place of A45", A45 being uncuped models, otherwise same part number-different pitch load on the motor but stamped with the same pitch number. These are not completely different props arriving at the same pitch, they are the same prop, except for the last 1/4" of the trailing edge.

Oh gee, here we go again. <br /><br />Backfire, if you’re saying that a cupped prop and a non-cupped prop can have the same pitch, then you’ve decided to agree with me. You must’ve finally realized that, in some boat applications, cupping a prop makes it more efficient and allows it to run closer to its actual pitch number (less slip).<br /><br />

Misrepresentation, can we allow this to stand?

In your examples of props with and without the cupping, the pitch is the same. The pitch of the prop has not been “misrepresented” by cupping. One just runs more efficient than the other does (in some applications).<br /><br />And if you are saying that a cupped prop can have the same blade geometry as a non-cupped prop, with the exception of a small part of the trailing edge, then you're learning. Obviously the location and amount of that particular cupping did not have an effect on pitch. Efficiency perhaps. <br /><br />Unfortunately that’s about where your mentality ends. There is more, but I fear it is over your head. I'll try. <br /><br />See, when double-cupping a prop, the cup can begin to intersect with the pitch line. When this happens it begins to have an effect on pitch angle. It depends on where that cup was made, as the trailing edge is not just at the tip of the prop. It exists along the entire blade. Cup can also intersect rake lines and will have an effect on rake. Cupping can also be altered in the area close to the hub, or anywhere along the blade. This is true especially for cleaver-style props. <br /><br />So is it that hard for you to understand that double-cupping has effects on the entire blade geometry, as it effects pitch angle and rake?<br /><br />I’ll say it again...”There is a huge difference in a prop originally designed with large amounts of cupping (double cupping), and one that is later modified with double cupping. Cupping has effects throughout the entire geometry of the blade, and thus the blade must be designed for the effects of that cupping. You can't really do this when modifying a stock prop, as the rest of the blade can not be changed to accommodate the new cupping. In other words double cupping can be designed into a prop for maximum effect. Where by modifying a stock prop afterwards, you only get what you get.”<br /><br />If you took a standard or cupped factory 15 pitch prop to the prop shop to have it modified by double cupping, you would unlikely be able to compensate for any effects on pitch angle and rake that the double cupping would cause (at least not without a total re-prop, which would change the geometry of the original prop entirely). <br /><br />It’s likely the prop would not obtain its original pitch. And that was Perry’s question, and my point. I’ve explained this the best I can Backfire.<br /><br />

"Where by modifying a stock prop afterwards, you only get what you get." <br />Like-What the hell does that mean?

You have a small mind. A prop includes many things other than cup (like skew, camber, rake, pitch angle, etc). And they all must work together for the prop to perform optimally. You can’t change one without having an effect on the other. Very few prop shops have the capabilities to compensate for these factors when double-cupping. You simply take your original prop, and double-cup it. Nothing more. Pitch usually changes as a result. Again, the point.<br /><br />

Many of the better prop people can adjust, modify a good prop to greatly out perform anything out of the box from the factories. Say like more stern lift, more bow lift,more pitch, less pitch, more rpm, less rpm, better handling, better hole shot, better top speed, cavitation control

I don’t think anyone has ever argued that props can’t be modified to perform better under certain conditions. The point was whether or not double-cup modifications effected original pitch. And in most cases it does.<br /><br />

-"get what you get"- I had to laugh at that, sorry.

I think you’ve backfired yet again Backfire.

 

[Forktail]

Re: Evinrude e-tec or Yamaha 4 Stroke

Thank you Lost Canadian!

 

[clanton]

Re: Evinrude e-tec or Yamaha 4 Stroke

I seen letter yesterday about service bulletin for all 2004 FICHTS and E-Tecs engine, I did not get details of recall, but all dealers should have letter and service bulletin in a few days. I hope only something minor.

 

[seahorse5]

Re: Evinrude e-tec or Yamaha 4 Stroke

I just checked the service bulletins and there are 2 bulletins just out that are only for 100 thru 250hp Evinrude DFI motors, 2004 only, not for any E-TEC models. <br /><br />The bulletins concern fuel return manifolds that may have not been made or sealed correctly by the vendor, and it shows how to inspect or replace it. These service issues were covered a long while back in a regular service letter to the dealers.