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Yamaha 115 underpowered

Hi all, just bought a 2015 hurricane 187 sundeck OB. Yamaha 115 has 305 hours. I foolishly did not test drive the boat, I trusted the seller and the engine fired up right away. On my first outing, the boat would not plane The boat has been kept in salt water and therefore has bottom paint. I suspected it was either prop issue or perhaps a bad cylinder, but engine sounded good. I took it to the local Yamaha dealer who immediately pointed out that the prop was too large to push a boat  like this with bottom paint, and that the boat is really under powered. He’s going to set me up with a new prop and do the normal maintenance. (And of course suggested a bigger engine re- power)  I guess I’m just looking for other folks with the same set up, because  this appears to be kind of a standard set up, as I understand it. I’m going to remove the bottom paint, which I know is a hassle and will require some gel coat repairs.
I just want the boat for some basic use, tubing and maybe a little water skiing. I used to barefoot ski, but at 61, I’m not looking for that anymore. Just easy recreation. Would welcome any suggestions. Mainly, will this 115 work for basic use and has anyone removed bottom paint?  I was naïve in not realizing the drag that it  creates.Thanks very much.


  • cjjjdeck
    cjjjdeck Member, Moderator Posts: 1,872 ✭✭✭✭
    I sympathize with your situation.

    Unfortunately, the dealer is correct in his "underpowered" comment to you.  Using the minimum horsepower (HP) formula of no less then 75% of the maximum HP rating for a boat, you will see from the specs shown below on your boat that the maximum HP is 200.  That puts minimum HP at 150 HP.  The boat is already well underpowered, add bottom paint to that and you've really put a strain on performance.  I cannot for the life of me understand boat owners that take a perfectly good boat and think it is a good idea to drastically under power it.

    2012 SD237 I/O Mercruiser 5.0L MPI ECT/ Bravo 3
    2012 Load Rite Elite Tandem axle trailer

  • Dawils
    Dawils Member Posts: 2
    Thanks very much.  It's funny that I see so many 187s with this setup.  I thought it would be OK, but I'll make the best of it for now, and either sell it or consider a future re-power.  Thanks again.
  • NJHurricane192
    NJHurricane192 Member Posts: 11
    My friend has a Hurricane 187 with a Yamaha 115.  His 187 planes out no problem with 6 people on it and is great for tubing.  His is bottom painted too.
    Would a 150 be better...heck yeah, but a good running F115 is sufficient power on a 187 to get on plane and do the things you listed.
    A new prop or motor tune-up might be all that's needed.  A slightly bent blade (sometimes not readily visible) or partial spun prop can dramatically reduce performance.

    I'm not sure but a 15 pitch prop might be the sweet spot for your set-up.  A new Yamaha branded prop (aluminum) is only $200 or so.  You can get a cheap no name prop for $75 but performance can be hit or miss.

  • NJHurricane192
    NJHurricane192 Member Posts: 11
    It's very rare for a 6 yr old F115 with low hours to drop compression on one or more cylinders.  If the motor is not fully performing its more likely to be something simpler to fix, like ignition or fuel supply.  if its ignition a Yamaha scan tool will usually throw a code.  Fuel issues don't always show up on the scan tool and can be more tricky to troubleshoot.  If the motor has been sitting it could be clogged fuel filters or gummed up fuel system.  A fuel starved Yamaha outboard can run perfectly at lower power settings but not perform well at WOT.   Look up "Yamaha VST"  (Vapor Separator Tank) that's a common source of fuel issues on Yamaha outboards.
  • RamandAng
    RamandAng Member Posts: 2
    I've got a 2001 Fundeck 188 with 115 HP Yamaha OB, basically the same boat. No bottom paint, on lake water, aluminum 3 blade prop...What we've learned the past year and half since owning is 1) It is a little tough taking out with full tank of gas but we will eventually get on plane, 2) Very difficult to get on plane with a max capacity of 10 adults/teens, 3) Almost impossible to get on plane with a full load of adults and full tank of gas, 4) Half a tank of gas, 3-4 people on board - no problem getting up fast!

  • bobg
    bobg Member Posts: 6
    I’ve had an SS188OB since 2011 with an F115txr 
    engine. No power issues. Does 42 mph with 2 people in boat. Gets up on plane quickly. No bottom paint or wax. 
  • Angryleprechaun
    Angryleprechaun Member Posts: 14
    I have a 2020 188SS with a 115hp Yamaha, no bottom paint.  With 2 people I'm at 37-38mph and no trouble getting out of the hole.  Right now I have the standard aluminum prop, but a stainless prop is forthcoming.  I'd love a 150hp, but I don't feel "drastically underpowered" at all. 
  • JJ_in_Florida
    JJ_in_Florida Member Posts: 15
    I have the exact same boat and year. I felt it was underpowered also. I do have smart tabs, no bottom paint. I switched out to a 4 blade prop with a little more pitch. It made a very noticeable difference. When you get the bottom paint off and change props you will be happier. Add smart tabs if you don’t have them.