Results 1 to 5 of 5
  1. 09-27-2019, 05:59 AM #1
    X270
    X270 is offline
    Member
    Join Date
    Apr 2017
    Location
    NWI
    Posts
    64

    Mercury 7.5 tune up?

    New to me Mercury 7.5 outboard...serial 4315612, 1975 model year?

    I’m having a hard time reading a scan of a manual for spark plug type, there’s a Perma Gap sticker on the side of the motor under the cowl but no model specified.

    Operating range says 4500 to 5500 RPM but no idle is mentioned, closer to 1200 RPM?
    1989 Hydra Sports X270

    1990 TE150SLESB 150HP
    Reply With Quote Reply With Quote
  2. SilverFox579
    SilverFox579 is offline
    Member
    Join Date
    May 2011
    Location
    Spangle, WA
    Posts
    6,221
    #2 09-27-2019, 09:12 AM
    Quote Originally Posted by X270 View Post
    Operating range says 4500 to 5500 RPM but no idle is mentioned, closer to 1200 RPM?
    Can't help with your question, just a pure SWAG, but 1200rpm seems way too high for idle to me. Had a 15hp 2-stoke Merc and it idled whole lot less than 1200rpm.
    _______

    Phil
    '09 Hewescraft ProV
    '09 150 Optimax

    Reply With Quote Reply With Quote
  3. JOE54
    JOE54 is offline
    Member
    Join Date
    Jun 2013
    Location
    LONGVIEW TEXAS
    Posts
    14,037
    #3 09-27-2019, 02:11 PM
    should idle 750-800 in N/ V40FFK OR L77V or BUHW will work
    .................................................. ...the scariest thing in life is the unknown ...................................
    Reply With Quote Reply With Quote
  4. X270
    X270 is offline
    Member
    Join Date
    Apr 2017
    Location
    NWI
    Posts
    64
    #4 09-27-2019, 03:24 PM
    I ordered a pair of QL77JC4 based upon a legible manual I found, hope they do the job.

    Thank you on the idle speed!
    1989 Hydra Sports X270

    1990 TE150SLESB 150HP
    Reply With Quote Reply With Quote
  5. SilverFox579
    SilverFox579 is offline
    Member
    Join Date
    May 2011
    Location
    Spangle, WA
    Posts
    6,221
    #5 09-28-2019, 10:41 PM
    Quote Originally Posted by JOE54 View Post
    should idle 750-800 in N/ V40FFK OR L77V or BUHW will work
    _______

    Phil
    '09 Hewescraft ProV
    '09 150 Optimax

    Reply With Quote Reply With Quote
« Previous Thread | Next Thread »