Results 1 to 9 of 9
  1. #1
    Member
    Join Date
    Nov 2004
    Location
    Clarksville, TN
    Posts
    1,839

    2017 Mercury 4 Stroke Ignition Problem

    I just got off the lake. I had a problem with my ignition switch. It turns all the way around without starting the engine. I kept trying until I finally got it to start and get back to the ramp. I guess it fell in to the right spot. When I tried it again on the trailer, it just spinned. I am obviously not a boat mechanic, but I assume I need a new ignition switch. Do you agree? How do I figure out which one to order online? I have 2017 Ranger Z518 with a 4 stroke Mercury 150. Thanks for the help.

  2. Member alli ss's Avatar
    Join Date
    Jul 2004
    Location
    Greenbrier, Ar
    Posts
    8,210
    #2
    Tighten it

    Phoenix 721 Pro XP, 250 Pro XS, aluminum gravel bar modified prop, paper sack tackle storage, ugly stik pro team, color c-lector pro team, TEMU Fishing Team

  3. Member
    Join Date
    Apr 2023
    Location
    Ohio
    Posts
    1,702
    #3
    Quote Originally Posted by alli ss View Post
    Tighten it
    Yep. There should be a threaded ring on the back of the key switch, behind the dash. Tighten that while holding the key switch on the front, in the desired position. Note: I had this happen on a Ranger with Evinrude, but I’m guessing it works the same with a Mercury on the same boat.

  4. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
    Join Date
    Apr 2008
    Location
    Greenville, SC (US)
    Posts
    97,865
    #4
    IF the entire switch ASSEMBLY is rotating around, then yes: Loosen the outside nut, turn the inside nut closer to the dash (1-2 turns) and then reinstall the outside nut SNUG.

    Now if the tumbler is just turning around and around inside the switch- that's a totally different problem.


    Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
    Still consider myself a "Marine Apprentice" after 48 years (learn something new every day).
    Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor

  5. Member
    Join Date
    Nov 2004
    Location
    Clarksville, TN
    Posts
    1,839
    #5
    It was a loose plastic nut. I got it just snug and it worked. Only problem I found was that if I tried to tighten the plastic nut real tight, the nut would break loose and spin. I tightened it again just enough that it didn't break loose and also put some threadlocker on it. Hopefully that stuff works on plastic too.

  6. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
    Join Date
    Apr 2008
    Location
    Greenville, SC (US)
    Posts
    97,865
    #6
    I would plan to order a replacement switch assembly from a Tracker Dealer, just so you are prepared and don't have to deal with it on the water.


    Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
    Still consider myself a "Marine Apprentice" after 48 years (learn something new every day).
    Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor

  7. Member
    Join Date
    Mar 2025
    Location
    Surprise, AZ
    Posts
    33
    #7
    Quote Originally Posted by tnbassin View Post
    It was a loose plastic nut. I got it just snug and it worked. Only problem I found was that if I tried to tighten the plastic nut real tight, the nut would break loose and spin. I tightened it again just enough that it didn't break loose and also put some threadlocker on it. Hopefully that stuff works on plastic too.
    Blue loctite can eat some plastics and degrade them.

  8. Member
    Join Date
    Nov 2004
    Location
    Clarksville, TN
    Posts
    1,839
    #8
    Quote Originally Posted by desertbirdaz View Post
    Blue loctite can eat some plastics and degrade them.
    Of course. Thanks for letting me know.

  9. Member
    Join Date
    Apr 2014
    Location
    SW, Ohio
    Posts
    21,432
    #9
    Quote Originally Posted by tnbassin View Post
    Of course. Thanks for letting me know.
    super glue maybe
    2022 z519 cup 225 merc 4s ser # 3B210484. 2--hds12 live units. 2 poles, atlas plate, ghost, hamby's, active target, merc digital gauges
    2002 basscat pantera 3 (dad bought new) sold 8-2-22
    2000 stratos 20 ss (bought new) 200 hp Rude ficht great boat/motor sold 11-21
    pulled by a 2500HD Denali will all the BANKS upgrades
    MAGA 45-47
    ASE/GM Master tech before tools