Powering a slippery cat with 20 hp. Fuel injected or carb.

Discussion in 'Outboards' started by Russell Brown, Feb 15, 2020.

  1. Russell Brown
    Joined: Jul 2012
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    Location: washington state

    Russell Brown Junior Member

    That was interesting. Apparently one has to sign up to even get the specs for an Evinrude. I'm not sure that I would want one, but it would be interesting to see what it weighs. I'd consider 15 hp if it was significantly lighter than a 20. The boat should cruise at about 15 with 15 hp.
     
  2. DCockey
    Joined: Oct 2009
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    DCockey Senior Member

    It is possible to see the Evinrude specs without registering. Select the range of interest and then find and click on "View Specs" near the upper right corner of the photos.
    Evinrude offers to 15 HP engines. One is a 4-stroke with carburetor. The specs look similar to the competition. I don't know if Evinrude builds it or buys it. The specs don't appear to line up with any other engines but I doubt Evinrude sells enough to economically manufacture it themselves. Portables Full Specs | Evinrude US https://www.evinrude.com/en-US/portables/portables-full-specs.html#tab=0
    Evinrude also offers a 15 HP HO engine which is a 2-stroke with their E-TEC system. It is significantly heavier than the competition and appears to be a derated version of their 30 HP E-TEC engine. E-TEC Full Specs | Evinrude US https://www.evinrude.com/en-US/e-tec/e-tec-full-specs.html#tab=13
     
  3. fallguy
    Joined: Dec 2016
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    fallguy Senior Member

    My all time favorite outboard was a circa 2000 30hp Johnson.

    <sigh>
     
  4. Richard Woods
    Joined: Jun 2006
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    Richard Woods Woods Designs

    I don't think Evinrude make their own 4st's. Not sure who does. But I do know, as a Evinrude tech guy told me, that the 15etec is essentially the same as the 30. And that the etec concept works better with bigger engines which is why they started with high hp. And that they sell the 15 as a kicker outboard to those who think a 30 is too big. The rep agreed with me that was crazy as they were the same engine. Marketing!!

    I did consider the etec30s for Skoota but never even got a quote from the local dealer despite phone calls and emails. So I decided if he didn't care about new business he would never care about warranty

    RW.
     
  5. Niclas Vestman
    Joined: Aug 2017
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    Location: Malmoe, Sweden

    Niclas Vestman Senior Member

    Really sorry to hear about Skoota. Painfull to see such a nice boat damaged that bad. Can only imagine what it must feel like for you. The joy and sense of accomplishment of completing a build of ones own design, only in reverse. Terrible. I really hope that's the last of bad things for at least a decade, and that only good things lie ahead for you!
     
  6. Russell Brown
    Joined: Jul 2012
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    Russell Brown Junior Member

    Changing a tiller handle electric start Suzuki 20 (without the trim/tilt bracket) is possible and they make a kit for it, but it's a bazillion parts and $460, so I'm not going to do it. I had thought about some non- factory linkages to make the tiller handle version work, but I'll likely buy a 2017 (pre-injection) Yamaha 20 that's set up for remote control, but without the trim/tilt bracket, which I won't have room for. Too bad, because the Suzuki could get substantially better fuel economy. The old Yamaha and new Suzuki are similar weights.
    I'll post a photo of the boat soon.
     
  7. Russell Brown
    Joined: Jul 2012
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    Russell Brown Junior Member

    So it looks like it will have to be a Yamaha F-20. The question (still) is whether to buy the newer fuel injected version that's 13 pounds heavier or the 2017 carb version. Yamaha can't tell me much of anything, except that they both should burn 1.8 gallons per hour at 5500 rpm. If we assume that Yamaha fuel injected motors are similar to Suzuki motors, then one would assume that the fuel injected Yamaha would burn less than the one with the carburetor at lower throttle settings.
    I'm pretty sure that the fuel consumption at reduced rpm's is more important to me than the extra 13 lbs, but I sure wish that someone at Yamaha could give me a rough idea of what to expect.
     
  8. Mr Efficiency
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    Mr Efficiency Senior Member

  9. fallguy
    Joined: Dec 2016
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    fallguy Senior Member

    I can share my experience with a Yamaha car beer rated 2.5hp.

    Horrid.

    The carb jets are miserably small and have a non-running lifetime of about 6 months before they clog. I have repaired mine twice in 2/3 years of ownership. Perhaps not a problem (washington?), but not good in Minnesnowta.

    The first cleaning was done by a Yammie dealer and cost $270. The second by me and cost me a few hours. These modern carbs have some epa **** on them that reduces the flow thru and helps create this issue.

    I can't speak to the efi, but I gotta believe it is better than bad.
     
  10. Russell Brown
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    Russell Brown Junior Member

    Mr Efficiency, Those numbers for the suzuki are terrible. I'd never seen that report, but it can't be right.
    Yamaha has nothing on the EFI 20, except the 1.8 GPH at 5500, same as the old model.
    I'm really a bit surprised that there aren't better figures for these small motors.
    What do you think, should I take the 13 pound hit and buy the fuel injected version on the hope that it burns less fuel when throttled back?
     
  11. DCockey
    Joined: Oct 2009
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    DCockey Senior Member

    Comparing fuel consumption numbers for different boats is similar to comparing fuel consumption numbers for road vehicles. Differences in the characteristics of the boats/vehicles can make as much or difference than the differences in engine efficiency. Fuel consumption by a engine depends on the engine speed and the power output.

    Russell, what fraction of the operating displacement is 13 lbs? That fraction will be approximately the relative difference in fuel consumption 13 lbs would make if everything else was equal including engine efficiency. If the total displacement is 2600 lbs then I'd expected a difference in fuel consumption of around 0.5 percent.

    My guess, but only a guess, is the EFI version will consume less fuel at part throttle than the carburetted engine. That is based on it being possible to more accurately control the fuel air mix with EFI than with a carburator. But that is only a guess.
     
  12. Mr Efficiency
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    Mr Efficiency Senior Member

    Maybe you misread the chart ? The figures are in litres, divide by 4 to get a close approximation of US gallons per hour
    RPM Av KM/H L/Hr Av L/KM 700 3.7 0.3 0.08 1000 4.2 0.6 0.14 1500 5.55 0.8 0.14 2000 7.3 0.84 0.12 2500 8.65 1.2 0.14 3000 9.75 1.8 0.18 3500 11.15 2.31 0.21 4000 12.6 2.595 0.21 4500 23.35 3.3 0.14 5000 28.05 4.2 0.15 5500 31.65 4.8 0.15 6000 34.5 6.1 0.18 6150 36.05 7.32 0.2
     
  13. Russell Brown
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    Russell Brown Junior Member

    The boat will weigh less than 600 pounds all up. I always choose a prop that lets the engine get up to the spec'd rev's, and the resistance is similar to a lighter planing boat, so It's not like I'm pushing a sailboat. The motor is fairly far aft between skinny hulls, which is why the extra 13 pounds seems like a lot. A 15 hp Honda powered the Grasshopper at a 15 knot cruising speed at 1 gallon per hour.
    I have been on the phone with the "experts" at Yamaha multiple times and I'm a bit shocked that no-one can even give me an idea about fuel consumption or even the difference between the EFI and carb.
     
  14. fallguy
    Joined: Dec 2016
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    fallguy Senior Member

    Those motor guys are all the same. Lotsa time if you are buying a stack of 425s.
     

  15. BlueBell
    Joined: May 2017
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    BlueBell Ahhhhh...

    How shocked are you at the terrible customer service from Yamaha Russell?
    You've mentioned it a few times and you haven't even bought their motor yet.
    Imagine how surprised you'll be when they ignore you after purchase!
    Buyer beware.
     
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