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Key West 239 FS - low rpm

Old 12-11-2018, 07:04 PM
  #21  
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Originally Posted by stephenson View Post
HTJ,

Want to make sure I don't get sidetracked, though ... you do believe I should not accept 5400 RPM as the normal range on my 250, right? That is the RPM when it is light ... with three guys and fishing gear with ice and bait, it is around 5150 RPM.
Originally Posted by LBI View Post
IMO U gotta get top RPM between 5800-6k for best results and to prevent the dreaded "making oil."
Yes and yes...for my money on any 4 stroke outboard you should be kissing the limiter when light and maybe 2 - 300 RPM off of max with your normal "heavy."
Manufactures/dealers get away with over propping as some large % of buyers are not overly savvy and typically running light....until the cousins come to visit and the evenings planned outing becomes a displacement speed only embarrassment for the fledgling new skipper.

You're on track OP
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Old 12-13-2018, 08:20 AM
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Sim Yamaha now shows the 17 inch available

https://www.simyamaha.com/category_s/13617.htm

Interesting though on the vmax sho the props are much bigger, the smallest size is 22 pitch. I found that
interesting on my Sho motor.
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Old 09-11-2019, 06:40 AM
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Did the OP ever get the 17 prop? And if so, what performance did you see? Thanks!
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Old 09-11-2019, 07:15 AM
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Hi clarky,

Not yet - been trying to find someone with like boat and motor combo who actually had a 17” SWS II.

One fellow finally got a 17” after having been promised delivery for months ... two weeks ago got it. His is a 239DFS without t top, but best info we have so far. He reports 50.5 mph at 5800 rpm on a very lightly loaded boat. So, way better ... but still not even close to 6000 rpm. Heavy boat with gear and four guys and ice, probably still in the 5400-5500 rpm range - again, better, but, well, one can see how the 19” is exactly the wrong size, even though it isn't clear what the best prop is.

I has two goals when I started this thread and another like it on keywestboatsforum.com ... the first was to find out what the right prop actually was for these boats, and to get the word out to owners and to KW about the right prop. Frankly, I would have been happy to see KW switch prop manufacturers if they needed to do so, to get the right size, but this wasn't done ... not really a lot of interest from KW and the loyalty factor came into play - I started catching flak from KW owners for inferring KW may have known the 19” was too big.

In any case, I have a great dealer - now that there may be 17” SWS IIs available, we’re going down the path to swapping. Yeah, it’s been a long time, but ....
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Old 09-11-2019, 07:23 AM
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I have a Key West 203FS and based on my research it seems that Key West props high to achieve top speed but not necessarily the most all around efficient prop. I have run all the calculators on my setup and it seems that going from 19p to 17p will be the best all around but I will loose a few MPH on the top end (which I am fine with). It makes sense for KW to always try to reach top MPH since that is all most consumers seem to care about.
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Old 09-11-2019, 07:41 AM
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Actually, there a couple of other factors, the most noteworthy being the Yamaha motor issue related to “making oil.” When the motors don’t run at high enough rpm, the rings don't seat well enough.

There is also increased load during acceleration, potential early cavitation during turns, etc.

Net in the case of the 239FS with 250 Yamaha, and in my opinion, the right props were not available from Yamaha, so some manufacturers just took the prop that was available ... I can’t come up with a better explanation.
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Old 09-11-2019, 08:16 AM
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Originally Posted by stephenson View Post
Actually, there a couple of other factors, the most noteworthy being the Yamaha motor issue related to “making oil.” When the motors don’t run at high enough rpm, the rings don't seat well enough.

There is also increased load during acceleration, potential early cavitation during turns, etc.

Net in the case of the 239FS with 250 Yamaha, and in my opinion, the right props were not available from Yamaha, so some manufacturers just took the prop that was available ... I can’t come up with a better explanation.
Overpropping a boat packing two undernourished Ethiopian testers and 40 gals of fuel makes for more impressive numbers on the performance report....works like a champ on uneducated buyers

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Old 09-11-2019, 08:21 AM
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Try a Mercury MIRAGEplus / Thunderbolt. I have yet to find a case where it will not equal or exceed the SWS II. Available in 17” and 18”

The Enertia / Q3 is another good choice. Borrow one of these and see for yourself. Experimentation is always the best way to dial a boat in.
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Old 09-11-2019, 08:40 AM
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The SWSII 17" has been available for months. I know b/c my dealer got me one in the spring. OP has been dragging his feet on this issue for over a year now. Either enlist the help of a pro like Ken at Prop Gods or do what most 250 owners on 22-24' boats have done - put a 17" SWSII on. Your procrastination has not helped your new motor and I don't know why you would continue to run the 19" as the performance is not good - bad hole shot and you cantt hold plane at lower speeds. Once you know you have the wrong prop, you research and take action. Simple as that. We went from a 19" Solas to a 17" Turning Point to a Rev4 to a SWSII 17" all within the first 50hrs. The SWSII 17" is nearly perfect compared to the others. Curious how many hours has OP run his 239 with the wrong prop?
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Old 09-11-2019, 08:52 AM
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Originally Posted by stephenson View Post
Hi clarky,

Not yet - been trying to find someone with like boat and motor combo who actually had a 17” SWS II.

One fellow finally got a 17” after having been promised delivery for months ... two weeks ago got it. His is a 239DFS without t top, but best info we have so far. He reports 50.5 mph at 5800 rpm on a very lightly loaded boat. So, way better ... but still not even close to 6000 rpm. Heavy boat with gear and four guys and ice, probably still in the 5400-5500 rpm range - again, better, but, well, one can see how the 19” is exactly the wrong size, even though it isn't clear what the best prop is.

I has two goals when I started this thread and another like it on keywestboatsforum.com ... the first was to find out what the right prop actually was for these boats, and to get the word out to owners and to KW about the right prop. Frankly, I would have been happy to see KW switch prop manufacturers if they needed to do so, to get the right size, but this wasn't done ... not really a lot of interest from KW and the loyalty factor came into play - I started catching flak from KW owners for inferring KW may have known the 19” was too big.

In any case, I have a great dealer - now that there may be 17” SWS IIs available, we’re going down the path to swapping. Yeah, it’s been a long time, but ....
Swap with me I need a 19 pitch SWSII. My cape horn 22os on 17 pitch not performing great.
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Old 09-11-2019, 08:53 AM
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I know some would do as you note, but I was more interested in helping not just MY particular application, but understanding WHY the wrong SWS II prop was on all the 239FSs I had heard of that had Yamaha props delivered - and, given the WHY then ensuring the correct props were put on this particular combo (239 FS and 250 Yamaha) - kind of giving back to the various communities that had helped me over the years.

The net of that is that there were not any Yamaha 17" SWS IIs available - for a LONG time. Glad you got yours this spring. One other guy was waiting - finally got his 10 days ago - and the numbers are better - not great (not even close to 6000 rpm on a lightly loaded boat), but better. His was the first instance of running a 17" SWS II on a 239 hull (and it was a 239 DFS without t top) that I had information from - I'm, sure there are more, and that is what I was searching for.

Given I got a single prop swap from my dealer - and, he is not local - the process I used will likely get me the right prop in the end - and, it will help notify everyone with a 239FS and 250 Yamaha that they should ensure they have a 17" SWS II vice the 19" SWS II.

Would still like to hear of others with 239FS, 250 Yamaha 4.2s with the 17" SWS IIs.

Throughout this, no one, even when they did comment, thought the 19" was the WRONG prop - so, there is some subtlety - likely based on where one is sitting.

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Old 09-11-2019, 09:28 AM
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Originally Posted by stephenson View Post
I know some would do as you note, but I was more interested in helping not just MY particular application, but understanding WHY the wrong SWS II prop was on all the 239FSs I had heard of that had Yamaha props delivered - and, given the WHY then ensuring the correct props were put on this particular combo (239 FS and 250 Yamaha) - kind of giving back to the various communities that had helped me over the years.

The net of that is that there were not any Yamaha 17" SWS IIs available - for a LONG time. Glad you got yours this spring. One other guy was waiting - finally got his 10 days ago - and the numbers are better - not great (not even close to 6000 rpm on a lightly loaded boat), but better. His was the first instance of running a 17" SWS II on a 239 hull (and it was a 239 DFS without t top) that I had information from - I'm, sure there are more, and that is what I was searching for.

Given I got a single prop swap from my dealer - and, he is not local - the process I used will likely get me the right prop in the end - and, it will help notify everyone with a 239FS and 250 Yamaha that they should ensure they have a 17" SWS II vice the 19" SWS II.

Would still like to hear of others with 239FS, 250 Yamaha 4.2s with the 17" SWS IIs.

Throughout this, no one, even when they did comment, thought the 19" was the WRONG prop - so, there is some subtlety - likely based on where one is sitting.
Okay I'll say it A 19 P anything is the wrong prop for that boat/motor combo.

And no need to make it a mystery, over and/or poorly propped boats with motors too low are delivered to consumers every day.

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Old 09-11-2019, 09:30 AM
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This was a guy I dealt with. 2018 Key West 239FS with Yamaha 250 4.2L
He had a 19 pitch Powertech OFS3 originally, it was too much pitch. he swapped to the same prop in 17 pitch, Powertech OFS3 Numbers below.

Last edited by ken2; 09-11-2019 at 10:22 AM.
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Old 09-11-2019, 09:49 AM
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HTJ,

As it turns out this is a mystery - hundreds of 239FSs are delivered every year ... a lot have 250 Yams on them ... almost all of these combos result in around 5400 rpm on a lightly loaded boat - everyone knows this, including Yamaha and Key West.

The mystery was - since everyone knows this - why were the combos still being delivered with 19" Yamaha SWS II props? Initially, I figured mine was a fluke, but as I scratched at it, with all the low RPM circumstances noted, it became clear (at least to me) the combo didn't work with 19" Yamaha SWS II prop - the 300 HP just barely does, and even these combos rarely do better than 5800 RPM, regardless of how they are loaded - some do, but most don't.

So, the wrong prop for the 250 ... I think everyone knew that ... the question then is why, right? Hundreds of 239FS in the last 2-3 years ...
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Old 09-11-2019, 09:52 AM
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Hi Ken,

The link didn't work ... yep, I'll bet the 17" prop did quite well - please repost the link ...

We've done biz before ..

Thanks.

Last edited by stephenson; 09-11-2019 at 10:09 AM.
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Old 09-11-2019, 10:08 AM
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LOTS of boat companies sell their boats with props that aren't necessarily great for real world applications.
Boats are a very custom thing.
For every guy like you that says, I want to turn the top end of the RPM range with my normal load in the boat, there is 10 other guys that don't care at all about RPM, or acceleration, or how it performs with Fuel in the boat, all he cares about is top end speed.
If you let him run a 17 and 19 back to back, and he got 5400@ 53 MPH with the 19, and 52 MPH @ 6000 wth the 17, with absolutely nothing in the boat, he'll grab the 19 every time, never think twice about it.
but your only at 5400 RPM.... "Hey it went faster, 5400 is in the RPM range, I wanna go fast ! and my RPM at cruise is lower too, so thats better right?"

Point is, regardless of what pitch they put on it, someone will be pissed about it.
On these boating forums, most of you guys do a lot more research on how you want the boat to run and what to expect, and adjust things to get it just right.
MOST boaters, don't care, they don't research this stuff, if they looked at the numbers I just posted, they would likely still pick the 19 for whatever reason.
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Last edited by ken2; 09-11-2019 at 10:27 AM.
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Old 09-11-2019, 10:10 AM
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Agree - big world of interesting people out there :-)

Could you repost the link for the numbers from the 17" Powertech? It didn't work.
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Old 09-11-2019, 10:16 AM
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This was a guy I dealt with. 2018 Key West 239FS with Yamaha 250 4.2L
He had a 19 pitch Powertech OFS3 originally, Similar numbers to you, he swapped to the same prop in 17 pitch, Powertech OFS3 he liked the 17 better.
Numbers below.


EDIT: here were his comments on load.
The numbers I provided were light load, maybe 1/8 gas, hard ttop, one person, no freshwater, no convenience center option, standard dual batteries.
I have been extremely happy with 17, much better hole shot, more responsive in general. I also pull kids on tubes and it does much better towing.

Last edited by ken2; 09-12-2019 at 05:28 AM.
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Old 09-11-2019, 10:24 AM
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Given those numbers, it is in incredible no brainer to use the 17" ... I suspect seats of the pant acceleration feel is pretty different, as well.

Any idea of boat loading?

End state of my crusade, is to summarize everything I've learned for the broader community - while making sure I was clear on which motor, whether the boats were light or heavy and had or didn't have T top, etc - i.e. and any extenuating circumstances that would skew the numbers.

Thanks, Ken.
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Old 09-11-2019, 10:44 AM
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I just emailed the guy and sent him a link, we'll see if he has anymore info for us.
I wasn't on the boat or anything, he just ordered the prop and send me the numbers.
Yes, I would guess stronger acceleration for sure.
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