Please note this thread has been inactive for 90 days. For the best results, please start a new thread.
Results 1 to 5 of 5
  1. #1
    Seaman
    Join Date
    Aug 2009
    Location
    Jersey Shore
    Posts
    50

    Default Spark Plugs for a 1989 85 Force

    I was recently told by a marine mechanic that I should switch from the Champion UL-18V surface gap plugs to a L77-JC4 plug with a .042 gap. He told me that "This plug fixes a problem with the newer unleaded fuels that the 89 year model engines cannot overcome otherwise. It vastly improves idling, low speed (eliminates the rumble & shudder) and burns cleaner at high speed. " However, I read a thread on this forum that says you should only use surface gap plugs because conventional gap plugs can burn a hole in the cylinder? I definitely don't want to do that. Which plugs should I be using? Can surface gap plugs perform adequately with today's fuel and will conventional gap plugs really burn a hole in the cylnder? Thanks.

  2. #2
    Commander
    Join Date
    Apr 2008
    Location
    Annapolis, Maryland
    Posts
    2,184

    Default Re: Spark Plugs for a 1989 85 Force

    Go and find another mechanic before that guy cost you lots of money. The surface gap plug is the only one specified by the manufacturer for your engine. Anything else is experimenting.

    Granted, there are speed shops for boats and cars and airplanes that develop their machines and processes separately from the manufacturer. However, these people have engineers, flow benches and CAD/CAM and have tested their product extensively.

    Somehow, I don't think your mechanic has the data to support his suggested changes.

    John

  3. #3
    Petty Officer 3rd Class Unbalanced's Avatar
    Join Date
    May 2009
    Location
    Stokesdale, North Carolina
    Posts
    89

    Default Re: Spark Plugs for a 1989 85 Force

    The only time a plug "fixes a problem" is when you replace whatever is in your engine with a brand new Factory Specifed plug...
    It's a big blue watery road...

    1992 Arriva 1800 - Mercury V 150

  4. #4
    Supreme Mariner Frank Acampora's Avatar
    Join Date
    Jan 2007
    Location
    Southeastern Pa.
    Posts
    10,280

    Default Re: Spark Plugs for a 1989 85 Force

    Ditto! Get another mechanic!

  5. #5
    Seaman
    Join Date
    Aug 2009
    Location
    Jersey Shore
    Posts
    50

    Default Re: Spark Plugs for a 1989 85 Force

    Thanks guys... he's not my mechanic, just someone who gave me some advice along the way. I'll use the surface gap plugs. Appreciate the input.

Similar Threads

  1. 95 Force 120 HP - Cold vs Hot Spark plugs Do I have the right plugs?
    By BajaFishin in forum Force & Chrysler Outboards
    Replies: 5
    Last Post: September 17th, 2007, 06:44 PM
  2. Spark Plugs Johnson 90 1989.
    By outboardkiwi in forum Johnson & Evinrude Outboards
    Replies: 5
    Last Post: March 3rd, 2005, 03:09 AM
  3. 1989 3cyl 50hp spark plugs
    By Keith Buchanan in forum Mercury & Mariner Outboards
    Replies: 7
    Last Post: June 29th, 2004, 12:41 AM
  4. Spark plugs needed for a 1989 Force 125?
    By Chris_NJ in forum Force & Chrysler Outboards
    Replies: 4
    Last Post: June 6th, 2004, 08:46 PM
  5. 1989 Force 50 spark plugs
    By Squeakit in forum Force & Chrysler Outboards
    Replies: 3
    Last Post: June 28th, 2003, 01:22 AM
  1. iboats Forum Directory - Over 100,000 forum posts organized by topic