1988 Mercury 9.9 2 stroke
Results 1 to 9 of 9
Like Tree14Likes
  • 1 Post By alawrence
  • 5 Post By BuckyBadger
  • 3 Post By HIKayaker
  • 2 Post By Albertaktm
  • 1 Post By Bobshouse
  • 2 Post By BuckyBadger

Thread: 1988 Mercury 9.9 2 stroke



  1. #1
    Contributing Member
    Join Date
    Nov 2009
    Location
    Southeast Wisconsin
    Posts
    3,851
    Member #
    12542
    Thanked
    10444 times

    1988 Mercury 9.9 2 stroke

    Hi folks,
    This is the engine that was on the 14' Lund I posted about earlier. During its first test run, when the nearby lakes were still ice free, the engine did not run well for me. So, I did a carb rebuild and cleaning, replaced the plugs and fuel filter, replaced the thermostat, and replaced the lines on the gas tank
    I put the engine back on the boat and took it to a small local river for a test drive. It started on the third pull and after adjusting the idle screw and the fuel mix screw, it was running nice and smooth at all speeds, once it was up to temperature.
    Now, my question for those that have experience with small outboards, while idling there was blue/white exhaust coming from under the cowling. My 2000 Mercury 8 hp kicker which is near identical to this 9.9 doesn't do this. What could be the cause? Possibly the exhaust gasket?
    Andrew
    turbobug likes this.
    The Gene Pool is in need of a lot of Chlorine!

    Better yet, drain the entire pool!

  2. #2
    Deadeye
    Join Date
    Feb 2008
    Location
    Northern Wisconsin
    Posts
    604
    Member #
    4900
    Thanked
    1709 times
    Best thing I think is to run it with cowl off and pinpoint where its coming from.
    Nothing is impossible......for the person that don't have to do it !!

    Benefactor Member NRA

  3. #3
    Certified Gunnut
    Join Date
    Jan 2014
    Location
    SW Ohio; Straits, NC
    Posts
    5,231
    Member #
    51002
    Thanked
    9941 times
    Could something on the engine have been burning off as it heated up? Especially after the carb rebuild?
    cajun56, alawrence and turbobug like this.
    NRA Endowment Life Member, SASS, OGCA, NC Watermen United
    “If liberty means anything at all, it means the right to tell people what they do not want to hear.” -- George Orwell
    "Corruptissima in republica plurimae leges."--Tacitus
    The more numerous the laws, the more corrupt the government.

  4. Remove Advertisements
    MarlinOwners.com
    Advertisements
     

  5. #4
    Contributing Member
    Join Date
    Nov 2009
    Location
    Southeast Wisconsin
    Posts
    3,851
    Member #
    12542
    Thanked
    10444 times
    Quote Originally Posted by BuckyBadger View Post
    Best thing I think is to run it with cowl off and pinpoint where its coming from.
    I gave that a try, but the exhaust fumes blocked visibility immediately. I will try it tomorrow while using a small fan.
    Thanks,
    Andrew
    The Gene Pool is in need of a lot of Chlorine!

    Better yet, drain the entire pool!

  6. #5
    Contributing Member
    Join Date
    Nov 2009
    Location
    Southeast Wisconsin
    Posts
    3,851
    Member #
    12542
    Thanked
    10444 times
    Quote Originally Posted by HIKayaker View Post
    Could something on the engine have been burning off as it heated up? Especially after the carb rebuild?
    It's coming up from the base of the cowl. I had everything wiped clean before putting it back together. I will try to pinpoint it tomorrow. I suspect it's an exhaust gasket issue.
    Andrew
    The Gene Pool is in need of a lot of Chlorine!

    Better yet, drain the entire pool!

  7. #6
    Sidewinder
    Join Date
    Oct 2019
    Location
    Lac St Anne, Alberta
    Posts
    108
    Member #
    147061
    Thanked
    206 times
    There should never be any exhaust coming from under the cowling The exhaust port dumps exhaust right through to the vents on the leg. Make sure it's warmed up then have a look. The direct air intake is under the cowling. This would choke out the motor quickly. Was the cowling fully seated when you did your first run after the service?
    gunscrewguy and alawrence like this.

  8. #7
    Contributing Member
    Join Date
    Nov 2009
    Location
    Southeast Wisconsin
    Posts
    3,851
    Member #
    12542
    Thanked
    10444 times
    Quote Originally Posted by Albertaktm View Post
    There should never be any exhaust coming from under the cowling The exhaust port dumps exhaust right through to the vents on the leg. Make sure it's warmed up then have a look. The direct air intake is under the cowling. This would choke out the motor quickly. Was the cowling fully seated when you did your first run after the service?
    I had the upper portion of the cowling (lid) off when I was running the engine. The exhaust seems to be coming from under the engine block. I will assume that there is a gasket that sits under it. I wonder if there is damage to it?
    Andrew
    The Gene Pool is in need of a lot of Chlorine!

    Better yet, drain the entire pool!

  9. #8
    Marlin Marksman
    Join Date
    Aug 2005
    Location
    Lompoc, CA
    Posts
    1,408
    Member #
    1543
    Thanked
    2481 times
    My old Suzuki motorcycle smoked like crazy, so do most chainsaws.

    Make sure to carry some oars with you though, just in case.
    alawrence likes this.
    6'x8' two man rooms with toilets. 23 Years in a Federal Penitentiary

  10. #9
    Deadeye
    Join Date
    Feb 2008
    Location
    Northern Wisconsin
    Posts
    604
    Member #
    4900
    Thanked
    1709 times
    Post your issue on MarineEngine.com, they'll tell you whats your problem is.
    Boat Repair Forum
    gunscrewguy and alawrence like this.
    Nothing is impossible......for the person that don't have to do it !!

    Benefactor Member NRA


Home | Forum | Active Topics | What's New | Subscribed Threads

Sponsored Links

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •