Mercury 15hp vrs 20hp outboard

Discussion in 'Dinghies' started by Blueone, Nov 13, 2019.

  1. Blueone

    Blueone Well-Known Member GOLD Sponsor

    Jan 24, 2007
    Lake Erie, Ohio
    2004 420 Sundancer
    Cummins 6CTA 450's
    We are looking at a new dinghy this year. I am more or less settled on a Highfield CL310 http://www.highfieldboats.com/classic-310/# It is aluminum hull and weighs 132lbs. Max outboard size is 20hp.

    Looking at the 15hp and the 20hp Merc they are identical displacement and weight. I have run into this before where the lesser hp motor is just a tuned down version. The difference in price is $500.

    Do any of you know if I will really notice the extra 5hp?.... can you tune up the 15hp to 20hp if you wanted to ?
     
    Last edited: Nov 13, 2019
    Air O'Nautical likes this.
  2. The Bill Collector

    The Bill Collector Well-Known Member GOLD Sponsor

    Jun 2, 2008
    Tacoma, WA
    450 Sundancer
    3126 Cat's
    I have a new Achilles 310AL with the Tohatsu 15hp electric start and it is more engine than my dingy needs. Look at the price difference mine and Mercury... They are made in same plant.
     
    Last edited: Nov 13, 2019
    Blueone likes this.
  3. Blueone

    Blueone Well-Known Member GOLD Sponsor

    Jan 24, 2007
    Lake Erie, Ohio
    2004 420 Sundancer
    Cummins 6CTA 450's
    Last edited: Nov 13, 2019
    The Bill Collector likes this.
  4. Blueone

    Blueone Well-Known Member GOLD Sponsor

    Jan 24, 2007
    Lake Erie, Ohio
    2004 420 Sundancer
    Cummins 6CTA 450's
    Your Achilles is almost identical to what I am looking at. Are you happy with the speed and size?... we are mostly just 2 adults but would like it to perform well with 4 adults.

    and is the electric start worth the battery effort and additional cost all be it very little?
     
  5. Caseclosed

    Caseclosed Member SILVER Sponsor

    147
    Jul 17, 2012
    SW Florida
    2007 44 Sundancer QSC 500 West marine 310 Dingy Raymarine Hybrid touch KVH
    Cummins QSC500 Vdrive
    I have a West marine 11.5 ft hypalon weighing 160 LBS with a 15 hp Mercury this combo gives me plenty of speed and planes very quickly.
     
  6. Blueone

    Blueone Well-Known Member GOLD Sponsor

    Jan 24, 2007
    Lake Erie, Ohio
    2004 420 Sundancer
    Cummins 6CTA 450's
    What davit system are you using?.... I was thinking the 11.5' would be a bit big blocking access to the swim platform door?
     
  7. The Bill Collector

    The Bill Collector Well-Known Member GOLD Sponsor

    Jun 2, 2008
    Tacoma, WA
    450 Sundancer
    3126 Cat's
    With 2 adults it gets a plane quickly and no issues. With 4 adults I do no attempt to plane. Our previous dinghy was pull start and not a big deal but for a few extra bucks it's now push-button and I added a USB & 12volt outlet into the top of the battery box. So, in short get the electric start and you won't regret it.
     
    Blueone likes this.
  8. importmonkey

    importmonkey Opinionated Member

    957
    Jul 9, 2015
    Middle River, MD
    2007 44 Sundancer
    QSC 500s
    We would have been fine with a 15hp, but when we had family over, I was happy to have the 20hp. Something very satisfying getting on plane with 4 adults and 2 kids. 15hp wouldn't have done that!
     
    Blueone likes this.
  9. Caseclosed

    Caseclosed Member SILVER Sponsor

    147
    Jul 17, 2012
    SW Florida
    2007 44 Sundancer QSC 500 West marine 310 Dingy Raymarine Hybrid touch KVH
    Cummins QSC500 Vdrive
    My boat has the hydraulic lift platform.12 ft is the the max boat that will fit on the platform.Total weight of my dingy is 270 LBS.
     
  10. Brent Nutting

    Brent Nutting Active Member

    274
    Mar 24, 2016
    Lk Saint Clair, Fair Haven, MI
    2002 480 Sedan Bridge
    10' Aventus RIB w/ 9.9 Merc
    Cat 3196
    Blueone, a good friend in the marina got the Highfield last year. It is a nice set up and he runs the 20hp Merc.
    I only have a small 10hp Merc and I am looking for a 20hp this season, but where we are located, we travel pretty far in the dink(s) and will spend all day (8 to 9 hours) running around the bay and bars.
    If it were me and the dink is rated for it, I would always go for the more hp. If / when you add a couple of adults the extra power will be handy.
     
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  11. Blueone

    Blueone Well-Known Member GOLD Sponsor

    Jan 24, 2007
    Lake Erie, Ohio
    2004 420 Sundancer
    Cummins 6CTA 450's
    I am impressed with the new design from Mercury for the 20hp...the tiller is pretty interesting...oil change/canister and weight are plus's too
     
  12. Brent Nutting

    Brent Nutting Active Member

    274
    Mar 24, 2016
    Lk Saint Clair, Fair Haven, MI
    2002 480 Sedan Bridge
    10' Aventus RIB w/ 9.9 Merc
    Cat 3196
    Opps, mistake in my previous response. I am looking to upgrade to a 15hp this season not a 20hp. My dink is only rated up to 15hp.
     
  13. Ricochet

    Ricochet Member GOLD Sponsor

    130
    Mar 10, 2009
    West Michigan
    1990 390 Express
    454 Mercrusier
    We have had the Highfield 290 for 3 years now we started with a 9.9 mercury which worked OK but with the short hull length it was sometimes difficult to get two people on plane quickly especially in rougher water last year I switched to the new 15HP EFI with the cool center mounted tiller it works perfect I top out at 20 mph WOT with one person haven't checked it with two but it can't be much different, I would recommend the 20 HP for the 310 like you said the weight is the same, I would go with the electric start if I had to do it over again.
    Rick
     
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  14. Lazy Daze

    Lazy Daze Well-Known Member TECHNICAL Contributor GOLD Sponsor

    Apr 21, 2009
    PA
    Various
    Various
    From my experience, it would be cheaper to buy the 20HP now, rather than "modify" the 15HP to be a 20HP later. One way to check is to compare parts lists (and part numbers) between the two engines. See what things are different and the costs associated with each. Account for labor either by paying someone or taking into account how much your time is worth.

    You might consider Smart Tabs, if needed. They would make a VERY noticeable difference in hole shot - regardless of the engine. Not expensive, either.

    One thing I've learned over the years... NO ONE in the history of boating has ever said "Shoot, I should've bought the smaller engine". :)
     
  15. The Bill Collector

    The Bill Collector Well-Known Member GOLD Sponsor

    Jun 2, 2008
    Tacoma, WA
    450 Sundancer
    3126 Cat's
    Oversized and under-utilized rather than undersized and over-utilized ??? I'm very happy with my 15hp and when it's just me, I have scared myself a couple of times...lol
     
  16. Boatingnut

    Boatingnut Member

    348
    Dec 18, 2008
    Saugatuck, MI
    2001 Neptunus 56 Express
    3196 Cats
    Agree with all of this, but go with the 20hp, and I doubt you will need the Smart Tabs. Not sure you need electric start, as the EFI starts easier than any carb engine. BTW, have you looked at the Suzuki? I have had one for 4 years now, simply an outstanding motor. They got into the EFI in the smaller motors early on, and it shows. Outstanding piece of machinery.
     
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  17. bobeast

    bobeast Dance the Tide SILVER Sponsor

    Oct 22, 2017
    Isleton, CA
    2002 310DA
    350 MPI w/V-drives
    The Tohatsu 9.9, 15 and 20 are identical engines. The difference is in the ECU and an intake restrictor. A new replacement ECU can be had for around $800. I plan to upgrade my 9.9 to 20 this winter.

    Tohatsu makes the small Mercury engines, so I would bet there is a similar upgrade path. All that said, it's more cost effective to buy the bigger engine up front, than to retrofit it later.
     
  18. susanandlance

    susanandlance Well-Known Member PLATINUM Sponsor

    Feb 10, 2011
    Florida
    2007 Sea Ray 36 Sedan Bridge
    8.1 mercruisers
    The 15hp will NOT plane with 4 adults, just tried it last weekend, get the 20hp. That being said the new tiller handle with shifter is nice, I'm very happy with mine
     
    Last edited: Nov 17, 2019
  19. b_arrington

    b_arrington Well-Known Member GOLD Sponsor

    Feb 21, 2007
    Setauket, NY
    2018 Back Cove 34
    Cummins QSB 6.7 480
    That new Mercury looks really nice. It might be enough to convince me to trade up from my 2 stroke Evinrude. The biggest reason I have a 2 stroke is for the weight savings over a 4 stroke. At 99 lbs that difference is really close now. EFI? Yes please - not looking forward to another carburetor rebuild. The adjustable tiller looks fantastic.
     
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