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Cavitation Problem on 27" toons with Yamaha 115

There is an obvious problem, which I am sure you are well aware of, with cavitation on 27" pontoon with Yamaha 115 motor. What is the manufacturer stance on this issue?  I read where one person received a longer propeller shaft under warranty?  There have to many people out there with this issue?  I have had the boat on the water 3 times and it runs terribly.  The trim is all the way down and still does not work right at 4,000 rpm.


  • ThePadThePad Member Posts: 8
    Just received a call from the Nautical Group (same day phone return call response was awesome) and he agreed to lower to the fourth hole mount at their expense. I will update the results.  
  • DdancersDdancers Member Posts: 110 ✭✭

    In the past I've called Nautical Group on another issue and they were very helpful.

    Good luck with the lowing , I know how you feel. Mine was so bad that the kids would lift up from there seat when it happen. I still get an occasional blow out, but no where as bad as the cavitation was. If the blow out get worst I'll ask what can be done. It might just be debris causing it. Yes please update us

  • joemjoem Member Posts: 1
    I am having the engine lowered tomorrow to the 4th hole on my 2015 2086 with 27" tubes.  I will keep you informed on how this works
  • DdancersDdancers Member Posts: 110 ✭✭
    Good Luck!
  • ThePadThePad Member Posts: 8
    It works better being lowered to the fourth hole, but the problem still exists with 4 or more people on board. The next step I guess will be the Whale tail Hydrofoil that was recommended by another user.
  • bafdafbafdaf Member Posts: 2
    I have the 2015 SW 240 SD with the 115 Yamaha and am experiencing the same cavitation problems and blow outs, although not consistently.  Does this occur with the 150?  There must be a final fix for this from the manufacturer. 
  • DdancersDdancers Member Posts: 110 ✭✭
    My unit was extended about 6 inches and corrected the cavitation, but I lost about 7 mph in speed. I've asked to have the motor raised 2 holes to see if that will be the sweet spot. Having a motor to low can create just as many problems as being to high.
    I'll let you know how it turns out. Just hope they get to it this season.
  • DdancersDdancers Member Posts: 110 ✭✭
    Well move the motor up two holes. Added 1.4 mph. 400 rpms and better trim response. I know the tubes are dirty so next year after they're cleaned I'll see how close my top end is to the original 27.4 mph. If at least 25 I'll let things stay as they are if less I'll raise motor one more hole and hope I hit the sweet spot.
  • ShoeDoctorShoeDoctor USAMember Posts: 6 ✭✭
    I have a 2015 SW 2286FCS with 27" toons and a Yamaha 115. 
    I am also experiencing the cavitation issue that you guys are referring to.
    If 2 or more adult are sitting on my front loungers cavitation is inevitable unless the motor is trimmed all the way down. Since I have fishing chairs in the rear, seating passengers behind the helm  is not an option when I am underway. That leaves me to place my passengers on the L-shaped lounger across from the helm. I have not had more than 3 passengers on board so far so I have no idea how bad the cavitation will be when I have 4 or more people on board.

  • DdancersDdancers Member Posts: 110 ✭✭

    I feel for you friend, and know just how upset you are.

    Yes they know they have an issue with the 27" tube setup. The sad thing is even if it's fixed like mine was they don't strive to do a 100% correction. After extending the shaft they should have raise the motor all the way up and tried it. If the cavitation was still there they should have lower one notch at a time to determine the optimum performance  position. I had to ask they lift it two notches and pay for the labor.

    If next year it's still ok I'll have pay to have it raised one more notch because I'm sure the performance will improve if there still is no cavitation. It's not just the cost that frustrates me it's the wasted time and seemingly lack of concern for my issues with this purchase. I'm not so sure Sweetwater is the problem name for these toons.

  • horsepen40horsepen40 Member Posts: 3
    Isn't it a shame that we are all having these problems with ventilation or "blowout" on a boat that cost what these have cost us. In good faith, I could never recommend a Sweetwater to anyone.  The factory won't step up and correct an inherent design problem.  Could this be the reason for selling the company to Bennington?  Now they can simply walk away and wash their hands of the whole dirty mess they have created?  The warranty usually doesn't follow the boat to the new owner of the company. They will warrant the ones they build, but the rest of us have been hung out to dry since Global no longer exists!
  • DdancersDdancers Member Posts: 110 ✭✭

    Sounds like you may be right. Glad I had work done before the sale, but still it's not right. I had an extension added to shaft which improved condition, but I lost several mph on top end. Recently had motor raised to notches to compensate and it improved the top end speed, but I get slippage after a few minutes running. Will maybe try a new propeller. This problem so far has resulted in costing me $125 raising the motor and will likely cost more before resolved. Right now I just want to corrected problem at a reasonable price. However if I knew I'd have this kind of issue would never have purchase the 115hp would have went with the heavier 150hp or another manufacturer .

  • DdancersDdancers Member Posts: 110 ✭✭
    edited February 2016

    Well another year coming up so I'm refreshing this Topic. I'm not looking forward to facing the same cavitation, and slippage issues, but not much choice so getting a head start on Forum to see if anyone has found a way to resolve the issue.  I was going to have propeller changed, but my dealer suggested I wait until the tubes were cleaned this year. However I did go to the Yamaha site and used the online propeller guide. The results came up with a recommendation Pontoon Performance Diameter: 14, Pitch: 11, or 14/12 or /14/13.   I asked the dealer what was currently on the motor and he stated a 17 inch or pitch but he wasn't sure witch, likely pitch. I was surprised because that was way more than what was recommended on the Yamaha site. I was a bit excited thinking that this might correct the condition. To be safe I called Yamaha and was again surprised when the Tech stated that 17 in diameter was the correct size for the setup. Now totally confused and wondering if anyone has try using a different propeller on the F115 LB engine with positive results

  • ThePadThePad Member Posts: 8

    I am getting ready for the upcoming year as well. Has anyone tried the Whale tail hydro foil?  It appears to be an inexpensive option at this time.

  • DdancersDdancers Member Posts: 110 ✭✭
    I've read some say it works well. However I'd check with dealer for possible warranty concerns.
  • ShoeDoctorShoeDoctor USAMember Posts: 6 ✭✭
    I have a 2015 Sweetwater 2286 FCS with the 27 toons and lifting strakes and a 115 Yamaha.
     I purchased my boat at the end of summer last year so I only got to use it a couple months. I love this pontoon boat. My only complaint is the cavitation issue I experienced a couple times. there is virtually no headroom in trimming the engine while underway. Especially if I have anyone sit in front of the helm. 
    I am getting ready to get my boat back in the water in the next week or two. I will wait and see what happens.
  • DdancersDdancers Member Posts: 110 ✭✭
    edited April 2016

    I had my SW 240 DF raised after the shaft was extended. I still have issue ,but think it's slippage instead of Cav. now. Had them clean the tubes and told them to replace the propeller hub if there was any doubt. Read someone had same problem but after replacing what appear to be a good hub problem went away. ShoeDoctor: I think you have the same issue as I had before shaft extension was installed. Many have an issue with the 27 inch tubes have to get it lower. Like you said trim is useless. I know if I still have problem I'll try different propellers. Problem is no trailer so dealer does all the work and it's $120 a pop just to raise or lower. Should be free, never was right. I'll let you know what results, hope you find a solution.

  • jdanieljdaniel Member Posts: 2
    I have a 2013 with the 27" toons, lifting strafs and Yam 115. My motor is mounted in the last hole. Just bought it and have had it out twice. It runs great and is faster than I expected. I have not had more than two people in it yet so we will see. I bought the whale tail but won't install it unless I too have the same problem
  • jdanieljdaniel Member Posts: 2
    Update. With several people in the boat I have the same problem. 5000 rpm at 20mph and on the edge of blowing out. No grip in the water. I'm already in the last hole. Anybody found a real cure yet?
  • DdancersDdancers Member Posts: 110 ✭✭
    Still an issue dealers hasn't corrected, but informed me they are in discussion with Sweetwater, and hope to have the means soon to correct problem. They did not try different props. My problem start around 4000 rpm, 70% of the time start slipping and can't exceed 16.2 mph. Sometimes by myself (not always) I can push to 6000 rpm 19.2 mph but the slipping is on off constantly and very noisy. With 6 persons onboard almost impossible to reach any speed over 12 mph without slipping and blow outs. Two years of true aggravation, I love the layout of my boat and in general I like my dealer. However the lack of urgency giving the investment is upsetting and can truly hurt a brand name. I can deal with the fact there’s a problem and even that it might take a while to resolve, but the lack of ongoing attention to resolve this is difficult to accept.

    I be willing to sell back, and purchase a model configuration that hasn’t got this problem.

  • fenwicktoonerfenwicktooner Member Posts: 1
    I'm experiencing the same problem with 27" toons and lifting strikes with the 115 yamaha. I have been given suggestions, lowering motor, 4 blade prop, water glide and jack plate. Does anyone have a good result with any of these?  Motor is in lowest position already.

  • DdancersDdancers Member Posts: 110 ✭✭

    End of story I HOPE!

    This is not the way I should have had to correct it (costly), but it worked, and after 2 years I just wanted it fixed.

    Replaced 115hp with 150hp.

    The 150 HP finally installed, and cavitation issue is gone. I was hoping to get better WOT Speed, but the ride was so sweet by comparison I'm just glad to be done with it. The service department claims they had it up to 33 GPS, I saw 31.8, but believe if well-trimmed 33 is likely there somewhere .Speaking of trim I can actually effectively use it now. Anyway I turned sharply into some wakes, and did multiple max turns and had no real detectable slippage, or cavitation.

    I don't believe any attempt to determine best engine height was done, think they just went by the book. I'm sure with some effort 36 mph would be within reach, but as I said what a sweet ride by comparison, it felt like a big cat clawing up a tree instead of a  spider trying to climb up a glass. Trolling speed is a little faster than I'd like, but not bad. I figure fuel consumption should be about the same because the 115hp was surely inefficient.

    Anxious to see how she is with 6 or more onboard.

    If the 6 person ride goes well, the fat lady can start singing.

    Engine Yamaha LF150 (long shaft) I’m told they think Prop is Stainless Diameter: 14.5, Pitch: 13 cupped

  • moombamoomba Member Posts: 3
    Seems like it is more than 1 cure to fix this problem.  I have lowered mine to the 4th hole and only got a little relief.  Trim is virtually useless, although I get a solid 30mph now.  I think you need a jack plate used to lower instead of raise the 115 outboard due to the excess lift of the bigger diameter pontoons at speeds above 20mph or so?   I like the idea of putting a shaft extension on and then raising the motor back up to the sweet spot.  I just don't think there will be 1 sweet spot due to how much the pontoon raises after 20mph.  The shaft extension would be a "fair" compromise or the jack plate would be a better solution at a higher price?
  • DdancersDdancers Member Posts: 110 ✭✭

    For me the extension didn't really help that much, and still slipped. I lost about 9 mph or more top end with it too. It's weird but I don't think 115hp could handle the prop needed to eliminate all cavitation. I recently hand 12 adults onboard with about 7 coolers and these weren't small people. I had to be right on the 15 person limit and with the 150hp I was able to hit just above 19 mph with no slippage. I hated to have to eat the cost, but the performance of a L150 XA  blows the 115 away and likely was the only true correction outside of having the transom mount replaced with the correct unit, and waiting another year with crossed fingers.

    Good luck hope you fine an easier solution.

  • joerteljoertel Member Posts: 1
    It's not just with the yamahas. I have the 135 ****, 145 hp evenrude and am having the same issue. This will be my 3rd year with the boat, and it's still not right, less than 15 hours on the boat. 2015 sweet water premium 240sd with 27 inch toons and lifting strakes. I have had it raised, lowered, had the extension put on taken off, 4 different props, and now the 3 toon put on. Still not right. Last I heard they were taking off about 5 feet of the lifting strakes off. Haven't gotten word yet. Any one else heard of pulling strakes on and off?  
  • pkcalpkcal Member Posts: 1
    Need advice....ordering new 2018 255 SDP slide boat this week.  Two toon boat, comes with 27" toons for extra flotation given weight of swim roof deck.  Anyone know if they changed/fixed something for 2017+ boats (seemed most were 2015/16 model years on this board) to prevent cavitation with 20" motor on 20" transom?  I'm going with 115hp Merc command thrust but need to know whether to go 20" or 25" shaft.  One dealer I talked to swears they always do 20" and have no issues and thinks 25" will run too deep/slow boat down even in top hole.  Anyone have a 255 swim deck with a 115 (20" or 25") with opinions?  Ideally I'd go with the 25" and could start with it in the top hole and adjust down as needed to minimize cavitation.  Price is the same, just don't want to go 20" and run out of downward adjustment.  Measurements would be great too.....specifically with a 25" in top mounting hole, how far is the motor cav plate below the transom pod on the boat.  Same Q on the 20" much adjustment below the transom pod do you have with the motor mounting holes?  Thanks in advance. 
  • gbownvagbownva Member Posts: 9
    i bought a 2018 SW2286 SB TT  25''  tubes with 150 hope no issues 
  • ShoeDoctorShoeDoctor USAMember Posts: 6 ✭✭
    Hey DDancers how has your pontoon boat been performing since you switched over to the Yamaha 150?  
  • ShoeDoctorShoeDoctor USAMember Posts: 6 ✭✭
    Update on my Sweetwater 2286 FCS Coastal Edition.
    My 2017 boating season was pretty much a bust due to my elderly parent's unexpected medical needs so my cavation issue remains the same.
    I dropped off my 2286 to the dealer on April 28th to once and for all get the cavation issue resolved. Here it is two months later and my boat is still there waiting on Godfrey to send the correct drive shaft for the extension kit. It took 8 weeks for the dealer to finally receive the kit (Friday June 23rd) only to discover that the shaft in the kit doesn't mate up to my shaft. I am a very patient man but this is ridiculous. I've lost two months of prime boating season with no resolution in sight.
    My dealer contacted Godfrey Saturday June 24th so we will see what happens.
    I will update this post as soon as I know something.

  • BoomerBoomer USAMember Posts: 310 ✭✭✭
    I have been waiting for a left front corner piece for 7 weeks now on my 2015 2286

    Dale Hollow Lake Byrdstown Tennessee
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