Welcome to Club Bennington

An official club forum for Bennington boats

Login Register

Performance was disappointing during first WOT

Discussion in 'Members Zone: Props and Power' started by Stevez, May 19, 2019.

  1. Stevez

    Stevez Well-Known Member

    Messages:
    122
    Likes Received:
    222
    Location:
    Kentucky
    I have a 2019 SXP25 tri toon with ESP and a F250 Yamaha. I didn't get into a lot of questions with my dealer around prop size/pitch, etc when I took delivery. They just said they have a lot of experience with matching props/platforms and that I would be fine. In fact, I don't know my specs yet (but will). I know it's 14.5 stainless with 4 blades. Yesterday on the Ohio River I opened it up for a very short time as I'm nearing the end of my break-in period. The water was choppy and I'm still trying to get used to the trim. The boat plowed through the chop nicely but when I did open it up I recall the RPM's getting close to 6,000 and my GPS showed I was only hitting 32 MPH. I don't need a speed demon and all but honestly expected much more than that. I was hoping I'd have enough power for 40MPH. I'm hoping it was the chop in the water and my inexperience with the trim and will keep trying and keeping better records. I of course will call the dealer when I have more data. Is 40 MPH for a 25 foot tri-toon unreasonable? It was me and my wife with 3/4 tank (50 gallon tank). Thanks. Steve
     
  2. Jack M

    Jack M Moderator

    Messages:
    6,937
    Likes Received:
    2,404
    Location:
    Petoskey Michigan
    I hit 38 ,with a 150 and a heavier boat ( RCW with an arch ) . With a lighter boat and a 250 I would expect close to if not over 45
     
    Spoiledrotten and Stevez like this.
  3. Vikingstaff

    Vikingstaff Well-Known Member

    Messages:
    1,570
    Likes Received:
    2,063
    Location:
    Michigan
    Hi there. I have a 200 Mercury Verado Pro on a 24’ SSBXP with just the SPS hull. Thus, you should be able to get above me with your motor. Once you get more data, post it. RPM/Weight-load/Trim/Conditions can be helpful.

    If I am at a full tank of gas (only a 30 gallon tank on my SPS), 2-3 people, I am about 38-40 mph on gps at WOT. I have a 200 Verado Pro, so I also have the benefit of a I6 + supercharger on my motor. Those are going to boost my performance compared to a normal I4 200HP. You are going to be slightly heavier than me with ESP + more gas + 1’ length. That said, you should still be above me in speed if you want to be.

    Starters:

    1) A four blade prop is going to be better hole shot, but also result in lower top end WOT speed. That is part of your issue. If that is what you value, keep a four blade. If you don’t need the BEST hole shot, switch to a 3 blade for better top end speed at WOT. Depends on what you want to maximize. You have a 250HP motor, so really you are going to be fine on either end of that spectrum once properly propped up. Which takes me to...

    2) IF its a 14.5p prop, that’s more ideal for a f200. I have a 16p Enertia on my 200HP Verado Pro, and I think I could still tweak to a 17p. I think you NEED to have a 16-17p range myself (maybe more, but don’t know). A 14.5 SEEMS UNDER-pitched for a prop on your F250 on an S-series. In looking up your RPM range at WOT it is 5000-6000 rpm per this source:

    https://www.rubexprops.com/boat-propellers/rpm-range/?make=Yamaha

    The ballpark is you drop about 200 rpm per +1 up in pitch you go. or add 200 rpm per -1 down in pitch you go. If you are pushing 6000rpm now, you got some room to play with pitch. I’d start at about a 16p if I were you for my first change up test run...maybe even a 17p.

    3) As you eluded to, playing with trim, and being on calmer water will go a long way on testing out where things are at. I wouldn’t bother recording numbers unless on a decent and calm day to get the most accurate speed for dialing it in a little bit more.

    4) Check out both the Yamaha and Mercury online prop selectors. You can data enter ALL your boat information to get somewhat nice ballpark prop recommendations. You can also modify those recommendations in the process for your intended use of the boat:

    https://www.mercurymarine.com/en/us/propellers/selector/#!/step-one

    http://www.yamahapropselector.com/propSelector/web/

    I am 99% sure you are decently under-propped. I think you need a +2-3 pitches in prop size.

    After all of this, I think you will see a jump in gps speed for sure. There could be some tweaking to do with the hole mount on your motor too, but honestly, I think your #1 issue is the pitch size of your prop. Perhaps prop type to, as that makes a difference (3 or 4 blade, curve of the cup, etc...)

    Hope this helps, and good luck. I look forward to hearing about how it goes. It might be a hassle right now. However, once you get it dialed in for your intended use and expectations, you will be good to go long term.
     
    Tomc, Chris Z, Stevez and 1 other person like this.
  4. Jb75

    Jb75 Well-Known Member

    Messages:
    171
    Likes Received:
    151
    Location:
    Greenville SC
    What Viking staff said. If you are indeed running at 6k rpm and 32mph I think you need to increase pitch. I run a Yamaha 250 on a 2250 g with esp and can easily run mid 40’s with the load and water you described. Get with your dealer and swap a few props and see what happens. I think you’ll be closer to 50 (light load) once propped correctly. I run a 15 1/2 x 16p Yamaha swsII prop. 47/48 lightly loaded and still 40 at maximum capacity. Have a 17p that gets me about 2 mph top end but lose some hole shot. 16 better for water sports. Good luck. You’ll get there
     
    Vikingstaff and Stevez like this.
  5. Stevez

    Stevez Well-Known Member

    Messages:
    122
    Likes Received:
    222
    Location:
    Kentucky
    Thank you all very much!! I really do appreciate it and I will track it some more and note conditions and get with my dealer. You all are great! Thanks.
     
    Vikingstaff likes this.
  6. Alicedream

    Alicedream Well-Known Member

    Messages:
    857
    Likes Received:
    951
    Location:
    Warsaw, MO
    Try a saltwater ll 16 or 17 pitch. I have Yamaha 300 on R series and I can hit 46-48 and probably more if I wanted to play around.
     
    Vikingstaff and Stevez like this.
  7. Jb75

    Jb75 Well-Known Member

    Messages:
    171
    Likes Received:
    151
    Location:
    Greenville SC
    I really can’t think of any water conditions where you are able to run 6k and only 32 mph. Although being in the river and dealing with current may have something to do with it. When you start to really measure and track performance make sure you track some runs up and down river. They also may have equipped you with aluminum prop (doubtful) due to river debris.
     
    Stevez and Vikingstaff like this.
  8. Stevez

    Stevez Well-Known Member

    Messages:
    122
    Likes Received:
    222
    Location:
    Kentucky
    IMG_1547.JPG Well I'm not 100% how close to 6,000 RPM's I was but feel it was fairly close. I was on the Ohio River in Louisville and it was windy and the water pretty choppy. I did also have the bimini top up which created drag, especially in the windy conditions. Wasn't planning on testing it, just decided to open in up for a few minutes. I know by my GPS I never exceeded 32 mph. I have included a picture I have showing the prop but it's not a good one. I'll get some more information and test again in better conditions. Thanks again. Steve
     
    Vikingstaff likes this.
  9. adkboater

    adkboater Well-Known Member

    Messages:
    1,327
    Likes Received:
    1,104
    Location:
    Tylersport,Pa
    Sounds just as everyone stated..... Prop issues. If that boat doesn’t clear 45mph there’s something wrong. I run a 24’ SPS w/200etec and can hit 42mph with my 16pitch. I prefer to run a fat eared 15pitch for all around use and tag 40 pretty easily and with 8-9 people on board we’re still cruising down the lake at 37mph. Make sure you write everything down and just adjust one piece of the puzzle at a time. Good luck!
     
    Alicedream, Vikingstaff and Stevez like this.
  10. Bamaman

    Bamaman Well-Known Member

    Messages:
    1,323
    Likes Received:
    246
    Location:
    Florence, AL--Tennessee River
    I was thinking your boat was delivered to the dealer with a get ready checklist on the boat and motor--showing serial numbers, etc. And I was thinking Bennington usually spec'd out the propeller to be used. Propellers are provided by the dealer, and sometimes they'll throw whatever prop they've got on hand. (Yamaha OEM props are quite expensive.) Like was said before, most 250 hp Yamaha motors get the Saltwater Plus II 3 blade propeller. My dealer always sets engines up 3/4 inch off the transom saying he can always drop it if there's any prop ventilation.

    (My dealer set me up with a M series prop, and not the proper Reliance prop for a F150. It cost me 4 mph and I was hitting the rev limiter, so the dealer ordered in a Reliance prop and swapped them.)
     
    Stevez, lakeliving and Vikingstaff like this.
  11. Stevez

    Stevez Well-Known Member

    Messages:
    122
    Likes Received:
    222
    Location:
    Kentucky
    Thanks; I have a call into my dealer to discuss. Appreciate the information.
     
    Vikingstaff likes this.
  12. TwoTone

    TwoTone Well-Known Member

    Messages:
    130
    Likes Received:
    345
    Location:
    Somewhere in Cabo... or Central Oregon...
    43 WOT for me on a Yamaha 200 (4 cyl.) on a 23" Benny... 4 Blade Props are super uncommon on the Bennington's... I see three different areas that could be the cause for your lack of performance - 1. Blades 2. Pitch 3. Mounting hole of the engine... Definitely going to take some trouble shooting, but when you're through, pretty sure you'll be over 40...
     
  13. Stevez

    Stevez Well-Known Member

    Messages:
    122
    Likes Received:
    222
    Location:
    Kentucky
    Thank you! I have reached out to my dealer but they have not responded yet. I took it out again yesterday on the Ohio and it was windy and very choppy. More like being on the ocean. I never could go faster than 32 again and paid closer attention to RPM's. Really never exceeded a little more than 5,000. I looked closer at the prop and it is a Solas (model 9553) 14.5 diameter with a 15 pitch. Again, it's a 4 blade. I'll talk to my dealer next week. Thanks again for all the advice.
     
    Vikingstaff likes this.
  14. 2fast4u

    2fast4u Well-Known Member

    Messages:
    84
    Likes Received:
    73
    Location:
    central North Carolina
    wrong prop for sure!
     
    lakeliving, Stevez and Vikingstaff like this.
  15. MATZKECLAN5

    MATZKECLAN5 Member

    Messages:
    8
    Likes Received:
    7
    I would think its a prop issue as well. Go on the Yamaha website into outboards, owners resources , and then performance bulletin. You can then see your motor used on a comparable Bennington and see how it performed and with what prop. That may help you.
     
    Stevez likes this.
  16. BURRIS PROP

    BURRIS PROP Well-Known Member

    Messages:
    62
    Likes Received:
    117
    Three blade prop with proper pitch we be faster then a four blade.
     
    Vikingstaff and Stevez like this.
  17. Stevez

    Stevez Well-Known Member

    Messages:
    122
    Likes Received:
    222
    Location:
    Kentucky
    Thanks again everyone. I did check the Yamaha site out and the closest model I could compare too showed the Saltwater Series II with a 15 1/4 diameter and 18 pitch produced 44 mph at 6,000 RPM. I think it was 40mph at 5,500 RPM. I'd take that and be very happy. Also, I'm a bit shocked at the trim as I don't notice any difference whatsoever when I adjust trim to try and increase speed. I never notice cavitation; just no discernible difference. On my old I/O (23 foot runabout), my trim was very noticeable and I could dial it in. Perhaps when I get the right prop I'll notice. Still working on it and appreciate the feedback. Steve
     
  18. Grasshopper

    Grasshopper Member

    Messages:
    9
    Likes Received:
    10
    I have the same issue with my trim. Boats a 2550 with an f250 and Saltwater II 15 1/2 x 17. Engine is mounted on the lowest hole and I think this is probably the issue. I cant see the cavitation plate while running with the prop all the way down or 3/4 up! Very little difference when changing the prop. Now the question is how many holes to move up?
     
    Vikingstaff and Stevez like this.
  19. Stevez

    Stevez Well-Known Member

    Messages:
    122
    Likes Received:
    222
    Location:
    Kentucky
    How do you like your prop otherwise? My boat is a 25 foot SXP, so yours is heavier I would assume. That sounds like the prop I maybe should have. And for what it's worth, the Yamaha site that showed the prop said it should be mounted on the 1st hole. I think mine is, but difficult for me to tell with boat in the water. Thanks.
     
    Vikingstaff likes this.
  20. Grasshopper

    Grasshopper Member

    Messages:
    9
    Likes Received:
    10
    I think the prop is fine. With clean tunes it did 43 at 5900. I think its mounted to low. Hole shot and turning are fine. Its just seems like it is missing some top end. From what I have read I think I should be able to see the cavitation plate at speed?
     
    Vikingstaff and Stevez like this.

Share This Page