Want to get rid of the ads? Become a member by registering today.
The Mariah Owners Club

Forum Left Top

Welcome to the The Mariah Owners Club.


Mercruiser 7.4 idle issues

Mercury MerCruiser

Reply
 
Thread Tools
Old 05-31-2010, 02:15 AM   #1

lowerthanu is currently offline
Posts: 7
Status: Stowaway
Join Date: Oct 2009
My Year: 1992
My Model: Z240
My Engine: 7.4 Bravo I
Gallery Images: 0


Thanks: 0
Thanked 0 Times in 0 Posts
Send lowerthanu:
a Private Message
 
Default Mercruiser 7.4 idle issues

Hey guys,
I have a 92 Mariah Z240 with the carbureted 454 in it that bought last year. I took it out once and it ran fine with no issues.

This spring I did a tune up on it including plugs, wires, cap, + rotor. I started it on the hose 2 times and it ran just fine. I took it out this weekend to the lake, and it fired up with no issues, but after 10 minutes of running, it started to have an idle problem. Any time I would bring it down to idle, it would start to run rough and smoke black out of the exhaust. Basically under 1200 RPM's in or out of gear it would do this. If I did not work the throttle, it would die and be very hard to restart. At anything over idle, it ran great with no issues.

Any ideas what the fix may be? Thanks again.
Reply With Quote
  • Old 05-31-2010, 02:45 AM   #2

    FreeSpirit 2777 is currently offline
    Posts: 3
    Status: Stowaway
    Join Date: Apr 2010
    My Year: 1997
    My Model: Z255 Shabah
    My Engine: 7.4l Bravo III
    Gallery Images: 0


    Thanks: 0
    Thanked 0 Times in 0 Posts
    Send FreeSpirit 2777:
    a Private Message
     
    Default Re: Mercruiser 7.4 idle issues

    The carter afb carbs had very small idle air passages and some fuels will clogged them up if it sits for some time..if this is the case you will need to remove carb and clean passages and reinstall.
    Reply With Quote
    Old 06-20-2010, 03:07 PM   #3

    tclark is currently offline
    Posts: 4
    Status: Stowaway
    Join Date: Sep 2009
    Location: Twin Falls, Idaho
    Find me on the Map
    My Model: 1997 Shabah Z210
    My Engine: 5.7L Bravo III
    Gallery Images: 0


    Thanks: 0
    Thanked 0 Times in 0 Posts
    Send tclark:
    a Private Message
     
    Default Re: Mercruiser 7.4 idle issues

    I have a 97 Mariah Z210 and it performs similarto yours. Starts and runs great on land on the hose and then once on the water starts right up but after 10 min or so of low speed or at idle starts to run rough or stalls. Very difficult to start after that. Also sometimes when you attempt to restart, it seems there is no power. You turn the key and nothing happens. This seems to go on for several minutes. Any suggestions.
    Reply With Quote
    Reply

    Bookmarks




    Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
     


    Similar Threads
    Thread Thread Starter Forum Replies Last Post
    5.7 inboard issues chriskeller82 Boating 101 4 07-24-2010 10:09 PM
    98 242 Z Nav light issues DRTutt Original Mariah Talk 2 05-10-2010 05:39 PM
    fuel issues murphysocc Mercury MerCruiser 9 09-14-2009 09:59 PM
    Prop Issues donb. Prop Talk 5 08-12-2009 09:23 PM
    Very rough idle dleeg5199 Original Mariah Talk 1 07-20-2009 02:41 PM



    Forum Right Top
    Forum Left Bottom Forum Right Bottom
     
    Right Left
    Member Login
    Forgot password?
    Forum LeftForum Right

    About the Club
    Age of the Mariah Owners Club:

    Total Members: 18,530
    Total Threads: 12,965
    Total Posts: 68,331
    Find us on Facebook Follow us on Twitter Subscribe to Mariah Owners Club on YouTube
    There are 260 users
    currently browsing forums.
    Forum LeftForum Right

    Find us on Facebook
    Forum LeftForum Right

    Club Sponsors
    Right Sponsor





    Forum LeftForum Right
    Right Right
    Right Bottom Left Right Bottom Right