Hot rod 9.9 merc

AlswaggAlswagg Posts: 2,579Member ✭✭✭✭✭
well we have completed modifying 3 different mercury 9.9.  Wow what a fun job. The test runs make it all worth the work.  All three are running awesome and sounding great too.  Carbs, tuned exhaust pipe, ported cylinders, and ported motor legs.   Fun fun today 
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Comments

  • Michael TMichael T Posts: 6,685Member ✭✭✭✭✭
    what? No pictures, just a tease? Geez!
  • AlswaggAlswagg Posts: 2,579Member ✭✭✭✭✭
    No photos of our modifications.  Sorry, but consistently have the most powerful 9.9 mercs on Lake Wawasee.   We mod these usually to go on 13' Boston Whalers.  A young person can drive a boat 9.9 model and under in Indiana.  We have hit consitantly between 15 and 18 hp.  Doesn't sound like much but we are nearly doubling the power output over a stock 9.9 Merc.   No we will not touch a Johnson or Evinrude.  
  • Michael TMichael T Posts: 6,685Member ✭✭✭✭✭
    ....get it, state secrets! :-)
  • AlswaggAlswagg Posts: 2,579Member ✭✭✭✭✭
    I learned quite abit from ole John R
  • Michael TMichael T Posts: 6,685Member ✭✭✭✭✭
    I bet! Up here kids can run up to 9.9 without the Feds being all over them too, one of the last places that aren't completely over-regulated. As kids we get some crappy old seized small out board and soak it with oil and hammer the piston with a block of wood and a baby sledge to get it going and then tune them up. It was a lot of fun with no friggin' X box and mall rats. I always say get your kids a boat for the summer and a sled for the winter plus a little duck hunting in the Spring and some deer in the Fall and they'll be too busy and having too much fun for drugs and other stupidity - end of my sermon!
  • AlswaggAlswagg Posts: 2,579Member ✭✭✭✭✭
    Yep. A lot of fun
  • Dream_InnDream_Inn Annapolis, MDPosts: 5,523Member, Moderator mod
    Yeah, my kids have been using an 8hp evinrude in our 8'6" dinghy.  Does ok, but time to get them a bigger toy.  Right now it will barely plane with the two of them in it.  Looking at something similar to the 13' whalers you are talking about.

    Dream 'Inn III -- 2008 400 Express

  • Black_DiamondBlack_Diamond Holland, MichiganPosts: 4,712Member ✭✭✭✭✭
    Sweet!  Be fun to test it out soon!

    2003 342FV "Black Diamond", 350 MAG MPI, 20P 4x4 Props, PC BYC, Holland, MI
  • AlswaggAlswagg Posts: 2,579Member ✭✭✭✭✭
    Dream I can keep an eye open for a Merc short shaft tiller for you.   
  • Black_DiamondBlack_Diamond Holland, MichiganPosts: 4,712Member ✭✭✭✭✭
    Finally ran my AB 9.5AL dinghy with the modified Merc 9.9 and a gps: 20mph with two of us in it!  Pops up super fast on plane now too (from stock). Great motor mod. 

    2003 342FV "Black Diamond", 350 MAG MPI, 20P 4x4 Props, PC BYC, Holland, MI
  • NavyCTRCNavyCTRC Pensacola, FLPosts: 303Member ✭✭✭
    Wow!  Double the output from a 9.9!!  That is impressive.  Too bad nobody has doubled the 270hp from 5.0's...then they would keep MT happy!!  :D
  • Michael TMichael T Posts: 6,685Member ✭✭✭✭✭
    @NavyCTRC....."google" whipplecharger.
  • AlswaggAlswagg Posts: 2,579Member ✭✭✭✭✭
    I have been working on a 9.9  four stroke mod also.  Carb, intake manifold, cam, and exhaust header. Plus a ported out motor leg.   Should be close to 20 hp.  This is with the Merc big 332 cc
  • Black_DiamondBlack_Diamond Holland, MichiganPosts: 4,712Member ✭✭✭✭✭
    edited June 6


    Here is my latest mod: Nauticus trim tabs. Hoping to test out later this week. Had pretty intense bow rise going on!

    tested today. What a difference!  
    Post edited by Black_Diamond on

    2003 342FV "Black Diamond", 350 MAG MPI, 20P 4x4 Props, PC BYC, Holland, MI
  • Dude_HimselfDude_Himself Charleston, SCPosts: 559Member ✭✭✭
    @Alswagg: how much does a custom 9.9 run? Might be in the market soon.
  • PickleRickPickleRick Posts: 536Member ✭✭
    I miss the old 2 stroke days where a simple carb swap took your 9.9 to 15 hp.


    Its good to see the epa hasnt taken all our fun away.




  • AlswaggAlswagg Posts: 2,579Member ✭✭✭✭✭
    Well Pickle Rick.  Not exactly.  A few more items are needed to get the 15 hp from 9.9.  Specifically the exhaust tube/header must be added.  This required the power hear removal from the motor leg.  Just adding the carb will net about 12 hp.  Now, if you swap carb , exhaust tube/header, port the motor leg and true the exhaust ports 1mm over sized.  This will net 18 hp at 6,000 rpm.  Cost runs about 1,500$.   But, this is legally still a 9.9 as per the serial number 
  • PickleRickPickleRick Posts: 536Member ✭✭
    edited June 17
    I was referring to the older 2 cycle motors. Yamaha in particular had a 9.9 2 stroke that became a 15 hp with a carb swap.

    Its cool seeing mods on a 4 stroke.  




  • AlswaggAlswagg Posts: 2,579Member ✭✭✭✭✭
    Pickle Rick  I was referring to the mercury 9.9 2 stroke.   
  • Black_DiamondBlack_Diamond Holland, MichiganPosts: 4,712Member ✭✭✭✭✭
    It is an awesome hot rodded 9.9 too! 🚀

    2003 342FV "Black Diamond", 350 MAG MPI, 20P 4x4 Props, PC BYC, Holland, MI
  • PickleRickPickleRick Posts: 536Member ✭✭
    I didn't realize mercury was still making a 2 cycle 9.9.   I thought they were all 4stroke now.  I dont browse outboards often.  Im sitting on a small stock pile of yamaha 9.9 4 stroke motors.  The only kicker i currently need is for my sailboat. Its a 1985 model 9.9, first year of yamahas 4 stroke 9.9 i believe. I love the fuel consumption or lack there of. I just dont like the weight 
  • Black_DiamondBlack_Diamond Holland, MichiganPosts: 4,712Member ✭✭✭✭✭
    The 2-stroke 9.9 (and the rest) are long out of production. A lot to be said about how much lighter the 2-strokes are, my 9.9 is about 67#, 4-stroke version is near 85# I believe. Every pound matters when it is at the end of one’s swim platform. 

    2003 342FV "Black Diamond", 350 MAG MPI, 20P 4x4 Props, PC BYC, Holland, MI
  • Dream_InnDream_Inn Annapolis, MDPosts: 5,523Member, Moderator mod
    I agree with BD.  I have a 3.3hp 2-stroke that I will never give up.  It weighs 28lbs.  I also have a 8hp 2-stroke that weighs 56lbs.  I may be selling that to a dock neighbor of mine, but it's a good one as well.  I'd love to have one of these 9.9's that are more like 14 or 15 on a nice hard bottom dinghy!

    Dream 'Inn III -- 2008 400 Express

  • StodgeStodge Lake St. ClairPosts: 2,587Member ✭✭✭✭
    I put a 10hp carb on my 8hp 2 stroke.  It will get my wife and I on plane in our 10 foot RIB.

    2002 FV 342 on Lake St. Clair - Past Commodore SHC - Vessel Examiner USCGAUX

  • zaverin1zaverin1 Harrison TWP ,MIPosts: 1,642Member ✭✭✭
    Ye my brother in-law has a 9.9 merc 4 stroke and it does pretty good. He has a hard bottom dinghy 
  • AlswaggAlswagg Posts: 2,579Member ✭✭✭✭✭
    I modify 1-2 every year.  These typically go onto 13’ Boston Whalers    The law in Indiana allows a 9.9 model to be driven by kids 10 years old.    We can take a 9.9 merc 2 stroke and produce up to 18 hp with extreme reliability.     Plus the sound awesome.  The 18,s with ported exhaust sound like a 125 dirt bike at 6,000 rpm     Braaaaap
  • Dude_HimselfDude_Himself Charleston, SCPosts: 559Member ✭✭✭
    Was that $1800 to mod, or a complete 9.9 engine?
  • Black_DiamondBlack_Diamond Holland, MichiganPosts: 4,712Member ✭✭✭✭✭
    Mod

    2003 342FV "Black Diamond", 350 MAG MPI, 20P 4x4 Props, PC BYC, Holland, MI
  • AlswaggAlswagg Posts: 2,579Member ✭✭✭✭✭
    Dude to modify.    It just makes for a much better engine.   The 4 stroke portables are such a terd.  
  • Handymans342Handymans342 Posts: 7,757Member ✭✭✭✭✭
    2 stroke equals diesel. LOL
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