can I convert my 5hp merc 2-smoke to a 6hp?

Discussion in 'Outboard Maintenance' started by TomFL, Jan 23, 2009.

  1. TomFL

    TomFL Well-Known Member

    Is it possible?

    What's required?

  2. The_Skiff_Shop

    The_Skiff_Shop Well-Known Member

    Don't think so. Pretty sure the 4 hp and 5 hp share the same bore and stroke which are single lung. The 6 hp is twin cylinder and shares the same bore and stroke with the 8 hp which in turn share many common parts with the 9.9 / 15 (which share a different, larger, bore and stroke).

    So, no, I don't think so but I'm sure someone will have a different answer. ;)

  3. Flyline

    Flyline Won "Do More With Less" Award!

    my answer is no..won't work.. for this model 4/5 model, 6/8 model and 9.9/15hp 2-stroke. ;)
  4. TomFL

    TomFL Well-Known Member

    Oh well, worth asking. Thanks CR & WS

  5. B.Lee

    B.Lee Well-Known Member

    Probably not worth spending the money, but you could likely massage another 1hp from it, and get your 6hp. Two strokes are pretty easy to tune up, but tend to become a little finicky if you get too radical.

    Shave the head a bit to increase compression, polish the intake and exhuast passages, etc.

    In the end it's still just a 5hp motor though.
  6. TomFL

    TomFL Well-Known Member

    Yeah, was looking for just an easy bolt-on sorta thing.

    The 5 horse serves it's purpose on the hi-sider as it's super-light and allows you to just drag the bhot off the trailer, throw the 5-horse, TM and TM battery on it and go fishing in places nobody else can get to.

    I don't need to run far in these out of the way places, so the "need" isn't really there for more HP.

    With 2 people on the boat the "want" definately is. It tops out at about 11.5 mph....

  7. Brett

    Brett > PRO STAFF <

    See, now if you had the merc 4 stroke 5 hp,
    all you'd have to do is bolt on a different carb,
    and you'd have a 6 hp merc.

  8. TomFL

    TomFL Well-Known Member

    yes but the 4-stroke carb is probably more $ than I bought this motor for!

    It was a deal I couldn't pass up, and glad I got it. Just would be "gladder" if it was a 6hp. Or a 7. Or an 8.....

  9. Brett

    Brett > PRO STAFF <

    Just for grins, checked the price of the 4 stroke 6 hp carb...$140 includes shipping.
  10. TomFL

    TomFL Well-Known Member

    Problem solved. I put a "1" in front of the "5" on the engine cowling. Plenty of power now, and only cost me $.50

    Why didn't I think of that sooner???

    :) ;)

  11. Un-shore

    Un-shore Well-Known Member

    ;D ;D ;D ;D

    Supress the urge to put a zero at the end, you could get yourself kild'
  12. Brett

    Brett > PRO STAFF <

    I don't see it that way a'tall...gots my fingers here, I can add this up!

    lemme see here 1+5 = 6   yep he gots him a 6 hp

    Now if'n we adds 1+5+0 = 6  nope, still only got's 6 hp

    oh well, better luck next time.

  13. TomFL

    TomFL Well-Known Member

    Brett, obviously the thinner and non-skid fumes have gone to your head.

    If we add the one to the five like you suggested, you should wind up with 15. 1 + 5 = 15. Then add the zero and that's how you wind up with 150.

    1 + 5 = 15.

    15 + 0 = 150.

    Very simple math, I'm not sure where you got off track.

  14. Brett

    Brett > PRO STAFF <

    I only have 10 fingers, I was doin' addin'.
    To git to 20, I'da had to shuck my shoes off'n my feet.
    Need to see my toes to do them big numbers.
    Doin' them largish type of numbers, you was probably doin' that new math!
    I larned the old math. I can mathematize up to 21 if'n I have to.
    But like phishphood, I'da had to put my hands in my pockets!

    As to the fumes, you ain't kidding, those products will kill you.
    Garage door was open, side door too, and both fans working.
    The smell is nasty! Can't wait to get to the varnishing!