25 HP Merc more power

Discussion in 'Outboard Maintenance' started by Lil_Tate, Jul 16, 2010.

  1. Lil_Tate

    Lil_Tate Well-Known Member

    25 HP 2 smoke Merc.
    Anyway to get more HP to it?
    Bigger carb?

    Can you make it a 35? or just a 30?
  2. Brett

    Brett > PRO STAFF <

    You can pour time and money all over that engine.
    Port and polish it, new reeds, new carb, new rings, new prop
    and after that you'd still have an older motor
    with corrosion problems and metal fatigue.
    Easier to sell the engine you have and buy a bigger outboard.

  3. mark_gardner

    mark_gardner I Love microskiff.com!

    how many times to we have to hash this one out ? :eek: jan should make this one a sticky ;D
  4. noeettica

    noeettica Well-Known Member

  5. Frank_Sebastian

    Frank_Sebastian Well-Known Member

    I would run gas for fuel, but a turbo-charger with intercooler with the dump valve set at 26 to 34 PSI just might work.

  6. Brett

    Brett > PRO STAFF <

    ;D that was priceless Frank...now I've got this mental picture
    of a blower sticking up through the top of the cowling. ;D
  7. noeettica

    noeettica Well-Known Member

    The Go-Ped guys run Nitromethane and bean Oil ...

    2 strokes are already "loop charged"

    I could be wrong but aren't blowers and turbos only for 4 strokes ...

  8. cutrunner

    cutrunner Cert. Yamaha technician

    they actually have turbo kits for the old v8 300hp evinrude so i guess they work on two strokes.. but i know personally than nitrous works on them. lol ten foot aluminum jon boat and a 15 hp evinrude on nitrous is fun
  9. Flyline

    Flyline Won &quot;Do More With Less&quot; Award!


    I had tried to modfied a 2003 25hp merc to gain more power but failed. It didn't last long as I thought it should be. Too much money and problems with this motor.

    If I were you, I'll look for nissan or tohatsu 25hp 2 stroke and change the gasket gain to 30hp. Or look for 40hp tiller :)
  10. TomFL

    TomFL Well-Known Member

    WS, where do you find those gaskets that bump motor hp up 20%???? :D :D :D

    Reminds me of Big Daddy Don Garlits telling a story about back in the day when he dominated drag racing. Everyone was trying to figure out his secret.

    They used to store all their parts/spare motors in the back of their cars (this is old days here folks!) and one day he was working on the motor and it started to rain. He hustled all his parts back to the trunk, dropping his head gaskets in a puddle on the way and figured he'd get them later. After the rain, he went out and picked up his head gaskets out of the puddle and finished rebuilding his motor.

    Next round, he sees all his competition soaking their head gaskets in puddles. They figured that was his secret.... :D

  11. Lil_Tate

    Lil_Tate Well-Known Member

    I get it, the answer is no.
    I just wanted to see about squeezing out a few more HP and not add any weight.
  12. Yoreese

    Yoreese I Love microskiff.com!

    I ran a stock 25 Merc on a BIG 16' Jon and never really wanted to go any faster. That boat could have ran a 40hp with no issues but would lose draft and really didn't want to beat me or my passenger up anymore than the 25hp would do. If I were using it on a LT25 I would say it should RIP!! The Merc 25 was one of the toughest small outboards made and put out plenty of power for its weight, a GREAT motor that will run small boats for many years to come.
  13. Flyline

    Flyline Won &quot;Do More With Less&quot; Award!

    I had it swap it out from the 30hp nissan powerhead years ago