Yamaha 115 Top Speed Experience

Pbakk

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Hello,

First time pontoon owner and still learning.

I have a 2019 22GSR with Yamaha 115 4 stroke and I noticed that my top speed is about 21 mph at 6,000 rpm. I was surprised to see the attached Yamaha Performance Bulletin indicates that a F115 on a Bennington 2275 GCW ran at 34.5 mph at 6,000 rpm. I do have Ultra Legs (Sea Legs) with a 2nd battery. Would the extra weight reduce speed by almost 40%?

While full throttle, I am not able to trim the motor without cavitation. Is this normal or maybe related?

I am curious what others see as a top speed with their Yamaha 115's.

My boat doesn't have pontoon lifting strakes. Maybe the lack of lifting strakes and extra weight of Ultra Legs is a reasonable explanation for the reduced speed.

Thanks for any thoughts that you may have.

Pat.
 

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Chris Z

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The boat that they tested not only had lifting strakes but it also sat on Bennington's elliptical pontoons. All the difference in the world.
 

goldnrod24

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My 22 footer with 2 logs and a black 115 ran 27-28 (gps). I added an express tune and fiddled with the transom height. My top speed was... wait for it... 27-28 (gps). Much better handling, but top speed never budged.

Expecting more from that heavy of a boat and a 115 (of any color) is a pipe dream. I ASSume you have a 2 log boat.

See my sig for top speed numbers for my new boat (21'/SPS/150).
 

DejaWiz

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Chris Z nailed it. Lifting strakes with twin ellipticals is the primary reasons for the difference in performance.

Without strakes a pontoon is plowing through water instead of planing on top of it. Added weight with dragging/surging points (such as exposed under-deck cross beams and Sea Legs) and the plowing effect is even more pronounced.

The good news is that you can have lifting strakes (and under-deck waveshielding...if you don't already have it) added.
The bad news is that it'll be pretty pricey to do, since a skilled aluminum welder will need to be hired.


Also, what prop is your F115 currently turning?

The ideal prop seems to be the Yamaha Pontoon Series 14 x 13 (part# MAR-PNTN3-V4-13 / 6H1-45978-00-00).
 
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Pbakk

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Thanks for all the feedback. Might have to wait on any more additions to the new boat at this time. Maybe save up for 3 log 150 Bennington, but I am guessing that will be a large jump in price.
 

DejaWiz

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Thanks for all the feedback. Might have to wait on any more additions to the new boat at this time. Maybe save up for 3 log 150 Bennington, but I am guessing that will be a large jump in price.
I edited my post above right before you responded in your thread - about the prop. Just wanted to make sure you caught my edit so we can try every angle to help you out.
 

Pbakk

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Chris Z nailed it. Lifting strakes with twin ellipticals is the primary reasons for the difference in performance.

Without strakes a pontoon is plowing through water instead of planing on top of it. Added weight with dragging/surging points (such as exposed under-deck cross beams and Sea Legs) and the plowing effect is even more pronounced.

The good news is that you can have lifting strakes (and under-deck waveshielding...if you don't already have it) added.
The bad news is that it'll be pretty pricey to do, since a skilled aluminum welder will need to be hired.


Also, what prop is your F115 currently turning?

The ideal prop seems to be the Yamaha Pontoon Series 14 x 13 (part# MAR-PNTN3-V4-13 / 6H1-45978-00-00).
Thanks for the prop suggestion. I will have to look at the pontoon this weekend. Not sure what the dealer put on it.
 

Bill N

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More info will help.
For instance if if it's rough water, the legs will catch in the spray and slow you down much more than they will on smooth water.
I always suggest that the first thing you do is get down on your belly and look underneath to verify that your darn legs are in full up position.
 

Pbakk

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More info will help.
For instance if if it's rough water, the legs will catch in the spray and slow you down much more than they will on smooth water.
I always suggest that the first thing you do is get down on your belly and look underneath to verify that your darn legs are in full up position.
Thanks - I have confirmed that the Ultra Legs are in the up position. I don't have lifting strakes, ellipticals, or under-deck waveshielding on my 2 log 22GSR pontoon. Wave action is usually not significant on my fresh-water lake and boating conditions. Usually have 2 to 4 adults, plus 2 batteries, 10 gallons of gas. Boating activity is basic cruising, occasional tube ride. Dealer has responded that my MPH is right at what they lake test for given the extra weight and boat setup. RPM's seems to be at the desired ~6,000 level at WOT.
 

Carlson80

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My old S21 with sea legs would go 26mph with the 115 and before sea legs it would go 30 on the gps. So I would expect yours to go 24 ish??
 

Bill N

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My old S21 with sea legs would go 26mph with the 115 and before sea legs it would go 30 on the gps. So I would expect yours to go 24 ish??
Those were closer to the numbers I was thinking as well.
Tubes clean?
 

Carlson80

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sunedog

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For another data point, I have a 2011 2275 GCW, Yamaha F115, two 25" round toons, no strakes and no under deck wave shield and the best I've seen with clean logs is 26 MPH (GPS).
 

Renegade34

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I had a 2006 Bennington 2 log with a 115hp Merc and Sea Legs. It would hit 25-27mph.
 

goldnrod24

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I think your issue, simply put, is due to the weight-to-horsepower ratio of your boat. The G-Series is a great boat, loaded with standard features. The addition of the Sea Legs and extra battery is the equivalent of carrying 3-4 extra passengers.

Happy boating.

Randy
 

Renegade34

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Also check to make sure you don’t have water in your pontoons. It’s happened to me more than once. Including my 2018 that leaked from new.
 

oldgreybull

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Hello,

First time pontoon owner and still learning.

I have a 2019 22GSR with Yamaha 115 4 stroke and I noticed that my top speed is about 21 mph at 6,000 rpm. I was surprised to see the attached Yamaha Performance Bulletin indicates that a F115 on a Bennington 2275 GCW ran at 34.5 mph at 6,000 rpm. I do have Ultra Legs (Sea Legs) with a 2nd battery. Would the extra weight reduce speed by almost 40%?

While full throttle, I am not able to trim the motor without cavitation. Is this normal or maybe related?

I am curious what others see as a top speed with their Yamaha 115's.

My boat doesn't have pontoon lifting strakes. Maybe the lack of lifting strakes and extra weight of Ultra Legs is a reasonable explanation for the reduced speed.

Thanks for any thoughts that you may have.

Pat.

I have a brand new 2021 20SSRX Tritoon with SPS package, sealed lifting strakes, wave shielding, with a VMAX 115 Yamaha, hydraulic steering and SS 3 blade prop. After the first 2 hours of break-in, with one person, trimmed up, GPS showed 38 mph at WOT. I was surprised; I did not expect that.
Hopefully when it's fully broken in that performance will translate into good pulling capability for a "Big Mable" loaded with 2 chunky grand-kids :).
My bride and I don't need that kind of speed; we're more inclined to S&M, that being Sunsets & Merlot of course! Cheers!
 
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Pbakk

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38 mph is fantastic for a 115. Big difference from my low 20s with my 22 GSR with no strakes, no wave shield, and standard 115 Yamaha and prop with Ultra Legs (Sea Legs). Enjoy - looks like you have it setup perfect for your use.
 
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