Pontoon Proping, Why the 400-600rpm rule per 2" don't work!

[ronb]

well since you asked.. I will give you the play by play on the steps when I changed out my 14x13p (max 5800 RPM) to a QuickSilver BlackMax 13.75 x 15p (max 5400 RPM) prop recently...

Here is my original (to me) prop, I wanted to try another size and everybody should have a spare (or 2)

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I bent out these tabs to release the lock ring

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wedged a prybar between the prop 'fin' and the down drive (gearbox) so it didn't spin and removed this nylock nut

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Next came off the locking washer itself

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and finally this insert that appears to be the key component that fits the splines, fits inside the rubber bushing inside the prop and holds the whole thing together. (it must have a real name, but I don't know it right now) my guess is this should be the only Yamaha specific part that you would have to worry about, getting the right spline size/count/diameter.

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The empty shaft, awaiting the new prop

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The old and new props side by side

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here you can see where you need to push the rubber insert out of the old prop (I used a small pry bar)

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And finally the insert next to the original prop

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pop that rubber insert into the new prop and re-assemble in reverse order...(which I also have pictures of, but I'll save you the bandwidth..)
enjoy...
-ron

[rancherlee]

What kinda speed are you seeing? What kind of pontoon setup (2,3, strakes?) reason for asking is the f115 has kind of an higher gear ratio (2.15:1) and if you have a planing type pontoon you should be seeing around 36-39mph @ 6300 rpm with your current prop. If you have a standard 2 tube you should still be pushing 30mph to turn 6300rpm other wise you are getting excessive slip beyond the 30% mark. If your beyond the 30% with a 4 person load then your current prop isn't getting the bite it should and might want to look for other solutions before getting a different prop.

[badmoonrising]

Make sure you always grease the splines before installing the new prop if you want it to come off

[Ryan]

What kinda speed are you seeing? What kind of pontoon setup (2,3, strakes?) reason for asking is the f115 has kind of an higher gear ratio (2.15:1) and if you have a planing type pontoon you should be seeing around 36-39mph @ 6300 rpm with your current prop. If you have a standard 2 tube you should still be pushing 30mph to turn 6300rpm other wise you are getting excessive slip beyond the 30% mark. If your beyond the 30% with a 4 person load then your current prop isn't getting the bite it should and might want to look for other solutions before getting a different prop.

With a light load and turning ~6300 your right on the money, it will run a gps 31.xx which the speedo shows around 36mph.... I wished the speedo was correct, lol. It seems very accurate up to 20mph then it gets off more the faster you go. This past weekend I had 9 people aboard and pulling riders on a large tube, max rpm was still 5900 with all of us onboard and it would drop to 5800 with a adult on the tube. If two adults are setting in the front seats it cavitates so bad that I have to be real carefull with the throtlle and turning is completely unhooked slipping. Moving people to the rear helps this a lot but you hate to have to do that on a large rig with so many guest. Oh and it took some finesse but the max mph while pulling a person on the tube was ~22.xx mph. I just wished Yamaha had a 14x15 I could call and order now. And depending on how I liked it order a 14x17 also for a light load faster cruising prop.

[Ryan]

Make sure you always grease the splines before installing the new prop if you want it to come off

Thanks for the advise. It's only been off that once yesterday but it still had lots of a white greese in it, I did re coat everything again though. Question: On the castle nut and cotter pin; would you recc. one slot on the nut that a tic loose with the pin in place [to where you can just turn the nut back and forth] Or the next one thats 'Very Tight'. Ya, from one slot to the next makes that much diff. here; as I put it back together for now the prop could be changed at the lake and not even use a wrench by just removing the cotter pin, the other would take a large wrench and a ton of effort or a rubber hammer. Thanks


Ryan

[Shopguy]

Went to Iboats and looked at the selection they had. Noticed that props for the 115 were mostly in the 13" range. So, I see your predicament. I also looked at the props for a 150 like mine. Lots of 15" props some 14's. But, what I really noticed was that they were both 15 tooth splines. This I don't know much about. What's the difference between the 115 and the 150 lowers? both obviously have a 15 spline shaft. anything else?
Maybe someone will find out if they're the same ....or not...and maybe this will broaden your search. It'd be cool if you could pick one from the 150hp list.

[Ryan]

Went to Iboats and looked at the selection they had. Noticed that props for the 115 were mostly in the 13" range. So, I see your predicament. I also looked at the props for a 150 like mine. Lots of 15" props some 14's. But, what I really noticed was that they were both 15 tooth splines. This I don't know much about. What's the difference between the 115 and the 150 lowers? both obviously have a 15 spline shaft. anything else?
Maybe someone will find out if they're the same ....or not...and maybe this will broaden your search. It'd be cool if you could pick one from the 150hp list.

Not for sure but my saleman told me that a F115 and F150 were Identical engines minus some computer tuning. A guy at the lake with a F150 told me one day that he thought there was a small displacment diff. as well though so Im not for sure. I dont mind taking the prop off right quick to check but 15 spine is what people has told me on the phone as well. Are you saying that you have seen something like a 14x15 or 17 for your 150? Do you have a link...all Ive seen in a 14" dia. is just up to a 13p so far. BUT.... Ive been wondering If these 'pontoon props' cup and so on are apples to apples with the factory Yamaha stuff.... you know. In other words like maybe thier 13p acts as If a 15 or 17 but..... who knows unless you try one. It just seems wrong to purchase a new prop and go the wrong direction from what it appears that I need, you know.


Ryan

[ronb]

Just to be sure you gave them a good looking over (I'd rather stay with factory stuff also if given a chance) but if you get no love from the Yamaha guys...

Flo-Torq II setup official page
http://www.mercurymarine.com/propellers ... /flo-torq/

I can't find it in text but the picture that they show says..
Adapts to:
Evinrude ®
Johnson ®
Suzuki ®
Honda ®
Nissan ®
Tohatsu ®
Yamaha ®

And that adapter thing does have a name.. "Aft Adapter" (one for the lame list)


A quick google search turns up adapaters for yamaha running from $35-94.99 depending on who is selling it.
-ron

[Bryden24shp]

Ryan, go to:
http://www.mercurymarine.com/propellers/prop-selector/#

Go through the guide. They should list your engine and tell you what they recommend for a Mercury prop. Go to Ebay and check them out. Buy a Flo-torque kit for a Yamaha and your set.

I just bought a brand new $480 Enertia for $150.00, shipped. If it doesn't work, relist and sell it. I've been doing this for years!

There is no majic formulas to propping. Every Application is different. Place to start is Cavitation Plate Height in the water. Don't even think about propping until you have the cavitation plate gliding ON TOP of the water.

[Ryan]

Just to be sure you gave them a good looking over (I'd rather stay with factory stuff also if given a chance) but if you get no love from the Yamaha guys...

Flo-Torq II setup official page
http://www.mercurymarine.com/propellers ... /flo-torq/

I can't find it in text but the picture that they show says..
Adapts to:
Evinrude ®
Johnson ®
Suzuki ®
Honda ®
Nissan ®
Tohatsu ®
Yamaha ®

And that adapter thing does have a name.. "Aft Adapter" (one for the lame list)


A quick google search turns up adapaters for yamaha running from $35-94.99 depending on who is selling it.
-ron

Thanks Ron ya Ive been looking at this. Its for sure an option If the size prop is available as well, just more additional cost again. Check out what Yamaha says about 'thier' hub and damping system: Below

Everyone is going to clain thiers the best but man Id rather stick to a Yamaha prop If poss.


I suppose the 14" 'Pontoon Props" use Yamaha's design?
http://www.yamaha-motor.com/outboard/po ... eller.aspx
I really like on that page where is says Endless prop sellection, LOL ....not

[Ryan]

Ryan, go to:
http://www.mercurymarine.com/propellers/prop-selector/#

Go through the guide. They should list your engine and tell you what they recommend for a Mercury prop. Go to Ebay and check them out. Buy a Flo-torque kit for a Yamaha and your set.

I just bought a brand new $480 Enertia for $150.00, shipped. If it doesn't work, relist and sell it. I've been doing this for years!

There is no majic formulas to propping. Every Application is different. Place to start is Cavitation Plate Height in the water. Don't even think about propping until you have the cavitation plate gliding ON TOP of the water.

I'll check it out thanks.

Ryan

[Ryan]

http://www.yamaha-motor.com/outboard/po ... 0~F115.pdf

This 13.5x17 looks like my only option with Yamaha to try but I darn sure dont know what to think about the 'Deep V' thing it says beside it? My factory 13.5x15 can stay as my heavy tow prop and be ok I suppose but I want my light load perf. prop to pull the r's down and hopefully find another mph or so; this 13.5x17 may do it but why does it have to have the other varible of the damn deep V crap; lol. I swear this is the way everything goes for me, ha

[rancherlee]

Just so you know, Yamaha bought Precision Propeller Inc. a few years ago, and most of there current props are exact copys of Turbo and Stiletto with Yamahas logo/naming scheme on them. There stainless "pontoon" prop is a Stiletto Star which is pretty dang cheap on the internet. I run the Turbo version which is the same prop with vents. This prop gets EXCEPTIONAL bite on the water, I really have to work hard to get it to vent.

[Littlehoe]

Hey guys, I just picked up a 2012 23 foot xcursion with 2 pontoons, I got the 115 yammy on her and I have now tried 3 different props from the dealer and can't figure out whats wrong. I use the gps for speed and I am getting a top speed of about 20 mph at 5500 rpm, the dealership said I should be closer to 30. However with the 15 prop I went to go full throttle and it just wound out the motor and pinned the tach at 7000. I pulled that back real quick... then with the 17 I went full throttle and still hit about 6600 rpm, so then with the 19 i hit like 6200 rpm. and still top speed about 20 mph. didn't matter if there was just 2 of us on there or 3 adults 2 kids a full live well of water and a pug chihuaha cross. It was 20 mph right away out of the hole and then cavatation over that... The dealership has my boat right now trying to figure out the issues but do you guys have any ideas? I don't know the length of the leg on the boat but could it need a longer leg if it is available? I really don't know much about boats so any help when I have to go talk to the dealership will be greatly appreciated.

[Ryan]

Just so you know, Yamaha bought Precision Propeller Inc. a few years ago, and most of there current props are exact copys of Turbo and Stiletto with Yamahas logo/naming scheme on them. There stainless "pontoon" prop is a Stiletto Star which is pretty dang cheap on the internet. I run the Turbo version which is the same prop with vents. This prop gets EXCEPTIONAL bite on the water, I really have to work hard to get it to vent.

Glad you found something that working great for you, I'd love to try that route but Im flat not going to risk putting a SS prop on this expensive of a engine. ALL the lakes around us are pretty stumpy and can't risk it. It just shouldnt be such an issue to find a alum. prop from Yamaha for my new rig.