outboard power on larger cruising cats

Discussion in 'Multihulls' started by Steve W, Aug 14, 2016.

  1. UpOnStands
    Joined: Nov 2015
    Posts: 681
    Likes: 14, Points: 18, Legacy Rep: 16
    Location: Sydney

    UpOnStands Senior Member

    can we keep it simple and return to the OP's original intent.
    Anyone care to comment on the carb vs. fuel injection alternative?
    on outboards of course.
     
  2. jorgepease
    Joined: Feb 2012
    Posts: 1,620
    Likes: 49, Points: 48, Legacy Rep: 75
    Location: Florida

    jorgepease Senior Member

    What more can be said about it lol. Anyone who considers carbs over fuel injectors is a masochist. Modern 4 strokes are as reliable as a new car.
     
  3. catsketcher
    Joined: Mar 2006
    Posts: 1,315
    Likes: 165, Points: 63, Legacy Rep: 790
    Location: Australia

    catsketcher Senior Member

    The Yammie 25 has a single carby. The Honda 25 I had had three. I am happy not to have injectors as you may get some dirty fuel and you can clean a carby in a few minutes but injector cleaning may need a special workshop which could be hundreds of miles away. A carby can be cleaned with some simple tools and some petrol.

    cheers

    Phil
     
  4. UpOnStands
    Joined: Nov 2015
    Posts: 681
    Likes: 14, Points: 18, Legacy Rep: 16
    Location: Sydney

    UpOnStands Senior Member

    You have had no problem with fuel evaporation gumming up the carbs?
     
  5. jorgepease
    Joined: Feb 2012
    Posts: 1,620
    Likes: 49, Points: 48, Legacy Rep: 75
    Location: Florida

    jorgepease Senior Member

    That's funny to hear that perspective. I run my fuel through filters, regular maint. and never have a problem. Carbs, don't use them for a couple weeks and things start sticking. Never will go back.
     
  6. cavalier mk2
    Joined: Mar 2010
    Posts: 2,123
    Likes: 55, Points: 48, Legacy Rep: 214
    Location: Pacific NW North America

    cavalier mk2 Senior Member

    Simplest thing to do with carbs is unhook the gasline and let the carbs run dry when powering off. No gummy bears.
     
  7. brian eiland
    Joined: Jun 2002
    Posts: 4,964
    Likes: 188, Points: 73, Legacy Rep: 1903
    Location: St Augustine Fl, Thailand

    brian eiland Senior Member

    ...and DO NOT utilize ethanol gas !!
     
  8. catsketcher
    Joined: Mar 2006
    Posts: 1,315
    Likes: 165, Points: 63, Legacy Rep: 790
    Location: Australia

    catsketcher Senior Member

    I don't run the Yammie 25 dry ever. It starts within 2-3 seconds after being left for up to a fortnight. It may need a squeeze of the fuel bulb if I haven't been to the boat for a while longer.

    From my experience it is two stroke that degrades to leave a residue in the carby. If we stick to four strokes then the fuel will be the same as what you have in your car. I run my Yamaha 8 two stroke dry and the little 3.3 when I can remember. I can take about 5 minutes to strip the 3.3s carby - gives me something to fiddle with when cruising. Do it once every two months but I am rather blase about the oil mix.

    It may be nice to have the better fuel economy of injectors but I am not sure they are found on the types of outboards that are commonly used to power cats - 9.9 - 30 hp. Looking at the manufacturer websites the Yamaha and Honda range still use carbys. (Up to 50hp high thrust at least)

    I have used these four strokes (Honda and Yamaha) for 17 years on Kankama. I once couldn't start the Yammie when I put in dirty fuel dregs. I cleaned it out and sailed on. So don't invert your fuel filling tanks and put an extra filter on (the ones on the outboards are very small) and according to my experience carbys will be very reliable. They have never stuck on a four stroke for me.

    And yes Brian. I always fill it up with Premium. I use so little it doesn't make much difference. We go through about 100 litres in months and months of cruising.

    cheers

    Phil
     
  9. brian eiland
    Joined: Jun 2002
    Posts: 4,964
    Likes: 188, Points: 73, Legacy Rep: 1903
    Location: St Augustine Fl, Thailand

    brian eiland Senior Member

    Do you fellows have this lousy corn ethanol additive they sell us here in USA??

    That stuff really screws up our gasoline product. And there are some folks that are heavy lobbying to increase it from 10% up to 15%...real CRAP
     
  10. catsketcher
    Joined: Mar 2006
    Posts: 1,315
    Likes: 165, Points: 63, Legacy Rep: 790
    Location: Australia

    catsketcher Senior Member

    Brian we can buy Ethanol - up to 10% in our E 10 fuel. Other fuels like Premium have an octane rating of 98 and no ethanol.
     
  11. cavalier mk2
    Joined: Mar 2010
    Posts: 2,123
    Likes: 55, Points: 48, Legacy Rep: 214
    Location: Pacific NW North America

    cavalier mk2 Senior Member

    I run high test here but I think in the states every grade gets some ethanol. Running the carb dry on my Yamaha I've gone a couple months without a restart no problem.
     
  12. brian eiland
    Joined: Jun 2002
    Posts: 4,964
    Likes: 188, Points: 73, Legacy Rep: 1903
    Location: St Augustine Fl, Thailand

    brian eiland Senior Member

    EVERY grade here in the US has ethanol, except if you have a station that stocks specifically non-ethanol grade.
     
  13. Steve W
    Joined: Jul 2004
    Posts: 1,824
    Likes: 63, Points: 48, Legacy Rep: 608
    Location: Duluth, Minnesota

    Steve W Senior Member

    I'd like to thank all for the their contributions. When I started this thread we had just gone to look at a Simpson 13m that was for sale in Florida. My son and his girlfriend have since bought it and we will be repowering it with a pair of Yamaha 25 HTs hence the thread. The boat is a bit of a project and we need to move it north to Duluth which is about as far west as you can get in the great lakes. The boat originally had saildrives but they were removed for unknown reasons and there are currently 2 Kubota diesels, 1 new the other rebuilt , 1 new sail drive leg, the other Mia.The engines are complete industrial units with no marinization parts and are up in the saloon. Having a preference for outboards anyway all this stuff will be sold and we will go the outboard route. We are going to have to come up with a very simple mounting system as we will be going down to the boat in a couple of weeks to prepare it for the winter but mainly to take lots of measurements and do sketches so we can fabricate the brackets at home before we do a 3 week work trip over Xmas where we will need to have a workable system by the time we head home, the goal being to launch in may and head north on the icw, so, how we mount the motors now needs to be simple, something we can install in a few days, it will not be the final solution but will still need to function well as its a lot of motoring between Florida and Minnesota. We do have 2 workable solutions figured out, the biggest problem is that Yamaha does not offer an extra long shaft on the 25 in the US…very dissapointing. Anyway, exciting times.

    Steve
     
  14. Spiv
    Joined: Jun 2007
    Posts: 221
    Likes: 16, Points: 28, Legacy Rep: 207
    Location: The Big Wide Blue Brother

    Spiv Ancient Mariner

    Steve,

    if you are planning to go through the ICW, you might have to remove the mast, motor all the way and you shouldn't have any problem with whatever installation you do.

    If you plan to go outside, I highly recommend you consider a strong solution and place those engines as far forward as you can.
    There is nothing more frustrating, damaging and possibly dangerous than short engines cavitating constantly in a head chop.
     

  15. UpOnStands
    Joined: Nov 2015
    Posts: 681
    Likes: 14, Points: 18, Legacy Rep: 16
    Location: Sydney

    UpOnStands Senior Member

    for Steve, great looking project - lot of boat there.
    does yours have the two double beds aft (as well as the doubles fwd)?
    The aft deck seems rather tight in terms of free space so assume the aft beds are there.
    twin outboards with access from the the top would be possible if you give up the inboard half of each aft double?

    in return you free up all that lovely aft space now occupied by the diesels.
    let's us know about your design process.
     
Loading...
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.