13 pitch vs 14 pitch?

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willy13
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13 pitch vs 14 pitch?

#1 Post by willy13 » Fri Sep 22, 2017 5:50 am

My 22 foot Fire & Marine Tritoon with a 2013 Yamaha 115 was spinning 6100 rpms with a Power Tech WBX3R13PYM90 prop (13 pitch, cupped, stainless). So I figured the easy thing to do is buy the same prop with a 14 pitch. I tested it last night, and it ended up still spinning 6100 rpms. I was surprised. I did my best to keep the conditions the same, but I really thought a 14 pitch cupped prop would certainly drop the rpm down on a 115 hp outboard even if my trim was off etc... They offer a 15 pitch, but I really can not see a 115 hp outboard spinning a 15 pitch cupped prop. Even though my tritoon has lifting strakes and is on the light side of tritoons. If I had to guess, I think my new 14 pitch prop is a 13 pitch. My old prop (13 pitch) was bought 4 years ago when I originally bought the outboard. While I know this shouldn't happen maybe the casting changed. I did email the supplier, so I will see what they say. Any adivice would be appreciated.

William

taylorjm
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Re: 13 pitch vs 14 pitch?

#2 Post by taylorjm » Fri Sep 22, 2017 6:43 am

Good luck. I was in about the same situation. I was running at about 6200 rpms, which is the max for my 90hp, and it didn't matter if I was fully loaded, towing a tube, or light load, so I figured I was hitting the rev limiter. I was at an 11p so I bought a 13p. Same quicksilver pontoon, extra cupped, same everything, just in a 13p. That should have reduced my rpms to about 6000rpms. Instead, it brought them up to about 6400rpms !! It did the total opposite! So I wondered if my 11p was actually worked on and was no longer an 11p, but it looked pretty standard, or the 13p was not correct. Either way, something was wrong. But at least now I know I wasn't hitting the rev limiter, and was running a true 6200rpms with the 11p, and that's my max, so I put the 11p back on and left it there. 2007 20' Bentley with mercury 90hp 4 stroke efi. I can get to about 27mph.

willy13
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Re: 13 pitch vs 14 pitch?

#3 Post by willy13 » Fri Sep 22, 2017 7:29 am

I plan on trying to measure the pitch myself. I am sure the internet will know how, lol.

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teecro
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Re: 13 pitch vs 14 pitch?

#4 Post by teecro » Fri Sep 22, 2017 7:38 am

[quote="willy13"]My 22 foot Fire & Marine Tritoon with a 2013 Yamaha 115 was spinning 6100 rpms with a Power Tech WBX3R13PYM90 prop (13 pitch, cupped, stainless). So I figured the easy thing to do is buy the same prop with a 14 pitch. I tested it last night, and it ended up still spinning 6100 rpms. I was surprised. I did my best to keep the conditions the same, but I really thought a 14 pitch cupped prop would certainly drop the rpm down on a 115 hp outboard even if my trim was off etc... They offer a 15 pitch, but I really can not see a 115 hp outboard spinning a 15 pitch cupped prop. Even though my tritoon has lifting strakes and is on the light side of tritoons. If I had to guess, I think my new 14 pitch prop is a 13 pitch. My old prop (13 pitch) was bought 4 years ago when I originally bought the outboard. While I know this shouldn't happen maybe the casting changed. I did email the supplier, so I will see what they say. Any adivice would be appreciated.

William[/quote]

What is the diameter? My friend has a brand new Bennington 22 foot pontoon with a 115 Yamaha and while I thought it odd it is spinning a 13.25" diameter by 17" pitch prop... So while your RPM did not change by upping the pitch you may simply still be sitting on the rev limiter due to a small diameter prop...
T CRO
2017 Berkshire CTS 24 RFX with Yamaha F150/Simomized 200
2015 Caravelle 16 EBo with Mercury 90

willy13
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Re: 13 pitch vs 14 pitch?

#5 Post by willy13 » Fri Sep 22, 2017 7:58 am

Its a 14" diameter. Does a warning go off when its on the rev limiter? I assumed I would be able to tell either by the engine kicking back or a warning buzzer going off. From my car days years ago, it was obvious when the rev limiters kicked in, engine would sorta skip. Are these new rev limiter so good thats its not even noticable?

In taylorjm case the new prop up the rpm. I suppose in my case I could still be on the rev limiter.

willy13
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Re: 13 pitch vs 14 pitch?

#6 Post by willy13 » Fri Sep 22, 2017 8:04 am

Actually I am sure its not on the rev limiter, because if I had a few more people the WOT rpm will drop down to 5900/6000.

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teecro
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Re: 13 pitch vs 14 pitch?

#7 Post by teecro » Fri Sep 22, 2017 8:19 am

[quote="willy13"]Its a 14" diameter. Does a warning go off when its on the rev limiter? I assumed I would be able to tell either by the engine kicking back or a warning buzzer going off. From my car days years ago, it was obvious when the rev limiters kicked in, engine would sorta skip. Are these new rev limiter so good thats its not even noticable?

In taylorjm case the new prop up the rpm. I suppose in my case I could still be on the rev limiter.[/quote]

I'm not totally familiar with today's outboards but if the electronics are as good on them as they are on some electronically controlled diesel engines you will never know that you are sitting on the rev limiter...

Another thought to keep in mind is are you sure the tach is on the correct setting?
T CRO
2017 Berkshire CTS 24 RFX with Yamaha F150/Simomized 200
2015 Caravelle 16 EBo with Mercury 90

willy13
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Re: 13 pitch vs 14 pitch?

#8 Post by willy13 » Fri Sep 22, 2017 8:56 am

Yeah the tach should be fine. Its the "all in one" that came from Yamaha with trim, tach, and warning stuff.

Bamaman
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Re: 13 pitch vs 14 pitch?

#9 Post by Bamaman » Fri Sep 22, 2017 9:26 am

I am sorry, but if an engine is making 100 RPMs over redline and there are no other issues (ventilation), I will leave the prop alone. Moving up 1 inch of pitch is not worth the investment.
'12 Bennington 24' SSLX Yamaha 150

willy13
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Re: 13 pitch vs 14 pitch?

#10 Post by willy13 » Fri Sep 22, 2017 10:52 am

[quote="Bamaman"]I am sorry, but if an engine is making 100 RPMs over redline and there are no other issues (ventilation), I will leave the prop alone. Moving up 1 inch of pitch is not worth the investment.[/quote]

In my case it is. The top speed is 30 mph, which is about what I slalom ski at. So I am running at WOT for slalom skiing. I would rather not be above the redline all the time. Now if I had a Yamaha 175 or 200 like I want, then I would agree with you. Also every little bit of speed is helpful for slalom skiing propper. I should be closer to 32. If I can get to 30.5 mph or 31, then it is worth it because thats what the boat is for.

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teecro
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Re: 13 pitch vs 14 pitch?

#11 Post by teecro » Fri Sep 22, 2017 3:28 pm

So let's ask this question. Did switching from a 13P to a 14P increase your speed any at all?
T CRO
2017 Berkshire CTS 24 RFX with Yamaha F150/Simomized 200
2015 Caravelle 16 EBo with Mercury 90

willy13
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Re: 13 pitch vs 14 pitch?

#12 Post by willy13 » Sat Sep 23, 2017 8:39 am

[quote="teecro"]So let's ask this question. Did switching from a 13P to a 14P increase your speed any at all?[/quote]

I roughly measured the props and the pitches are correct. Last night I was able to test the 14 pitch with more people. Too my surprise I was able to hit 31 mph and 6100 rpms with 4 people. With the 13 pitch I could hit 30 mph with 2 people at 6100 rpms. So yes I gained a bit of speed. I am beginning to think that maybe I am on the Rev limiter. Since the pitches measured to be correct, I will be trying the 15 pitch.

Thanks so much for the help. Oddly I enjoy playing around with stuff, as long as I eventually figure it out. :biggrin2

willy13
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Re: 13 pitch vs 14 pitch?

#13 Post by willy13 » Sat Oct 14, 2017 8:09 am

PowerTech was able to make me a 15 pitch WBX3 prop. I tested it yesterday, and I am now seeing a RPM drop, so I guess I was on the rev limiter. I must say that these rev limiter make it hard to figure out how much to drop pitches. With that 13 pitch I was probably seeing well over 6100 rpms but didn't know since the rev limiter kept it below that. Yesterdays conditions were not ideal for testing. It was rough for Canandaigua lake, probably not for some of you on these really big lakes. Anyways, I was able to get to 5800 rpm's at 32 mph. It would pop up to 5900 when I hit a wave just right. Never blew out though. This was with just me in it. I think I might be able to raise the outboard 1 notch now, I wanted to before but with my RPM so high it was not an option. I hope to test in calmer waters today.

Should I be seeing higher or lower RPMs in calm water? What about speed? I am guessing both RPMs and speed will go up in calm water, correct?

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Re: 13 pitch vs 14 pitch?

#14 Post by willy13 » Sat Oct 14, 2017 4:15 pm

It was much calmer today! Basically ran the same, 32 mph at 5800 rpm. I was able to hit 33 if i trimed up to get the rpm up. This time I had another person with me. I could see the cav plate, but it looked like it was just under the water. I will definetly be raising the outboard 1 notch. I have a yamaha mult-function gauge for measuring the trim. I had the trim at 3. I had to go to 3.5 in order to get the RPMs up.

captain28570
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Re: 13 pitch vs 14 pitch?

#15 Post by captain28570 » Sat Oct 14, 2017 10:08 pm

Props of the same make can still be different in pitch even if its says its the same pitch. Power Tech is famous for being really off on the pitch of their props. Even when I have called them directly they admitted their props vary on pitches.

I'm running a rebel prop on my G2 right now. They tend to act like 1 to 2 pitches higher. So a 17 acts like a 18 or 19 pitch. Prop Gods Ken a well known prop guy in Florida stated he had experienced that with Rebel props.

I tried a 19 pitch Viper prop. It turned the same Rpms as the 17 pitch Rebel I'm using now.

So today I tried a 17 pitch Enertia. Its 14 1/2 diameter. I turned 6000 rpms at 43 MPH. The Rebel 17 by 15 1/2 prop today turned 5600 at 42 mpg. My G2 needs to be 5600 to 5700 for best performance.

I kinda figured an 18 pitch or 19 pitch enertia would be perfect pitch for me. But the diameter gets smaller as the pitch goes up. So I wanted to try the 17 anyways. The G2 being a 2 stroke has so much low end torque I cant use a diameter less than 14 1/2. Its loses to much midrange speed.

If they made an 18 or 19 pitch Enertia in 14 1/2 or 15 diameter I believe my boat would hit 45 MPH. I might see if the prop guy can make the 17 Enertia an 18 pitch.
2017 22 Manitou Aurora LE SHP Tritoon Evinrude G2 HO 150

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