Results 1 to 7 of 7

Thread: Engine cuts out

  1. #1
    Join Date
    Jul 2007
    Posts
    24
    Rep Power
    0

    Engine cuts out

    I've got an old 22 Donzi Classic, 454 Mercruiser with a Bravo One drive. I have an intermittent problem. The motor runs great most of the time, but sometimes at or near WOT the motor starts cutting out until I back off the throttle. If I don't back off, the motor will actually quit. Sounds like fuel starvation to me but I'm not sure where to start trouble shooting it. I've replaced the fuel filter. It has an Edelbrock carb. Weak fuel pump? Anyone had similar symptoms?

  2. #2
    Join Date
    Nov 2010
    Posts
    84
    Rep Power
    0
    Install a fuel pressure gauge at the carb, it should maintain 7 psi or more with the engine running at any throttle position. If it drops below 7 psi, say 3 - 4 psi, you have a weak (or insufficient flow rating) fuel pump. If it maintains 7 psi or above then the carb needle & seat may be too small for the engine demand.

  3. #3
    Join Date
    May 2003
    Posts
    2,310
    Rep Power
    24
    The lowest tech suggestion of all ...
    Make sure your gas tank vent isn't blocked in any way from dirt or corrosion.

    That little tip I first picked up from the good folks here . It's free and only takes a few minutes but it has the potential to save you a lot of expense and aggravation.
    Just because something's old doesn't mean you throw it away !

  4. #4
    Join Date
    Aug 2003
    Posts
    1,848
    Rep Power
    22
    Quote Originally Posted by Morgan's Cloud View Post
    The lowest tech suggestion of all ...
    Make sure your gas tank vent isn't blocked in any way from dirt or corrosion.

    That little tip I first picked up from the good folks here . It's free and only takes a few minutes but it has the potential to save you a lot of expense and aggravation.
    Even lower tech, just remove the gas cap to check for vent blockage.
    Cheers,
    Pismo
    1996 22 Classic
    Red with Stainless Windshield
    Stock Gen VI 502 Magnum MPI-415hp
    Stock Bravo I
    25" Mirage Plus
    74.5mph best @ 5050rpm GPS (Speedo said 80)
    27" Labbed Mirage Plus
    75.5mph best @ 4800rpm GPS (Speedo said 82)

  5. #5
    Join Date
    Jul 2007
    Posts
    24
    Rep Power
    0
    thanks guys, sounds like good advice.

  6. #6
    Join Date
    May 2003
    Posts
    2,310
    Rep Power
    24
    Quote Originally Posted by Pismo View Post
    Even lower tech, just remove the gas cap to check for vent blockage.
    OK, I like that . You can work on my boat anytime !
    Just because something's old doesn't mean you throw it away !

  7. #7
    Join Date
    Oct 2012
    Posts
    719
    Rep Power
    0

    check fuel pressure

    Fuel pressure is a good place to start.
    My 502 with 750 Edelbrock seems to run fine with about 6psi. My stock Carter electric fuel pump is internally regulated so I've not ever messed with it. The pressure doesn't ever seem to drop even at 4600rpm...
    Thank you, Patrick
    1994 18' Classic 350Mag Alpha

    Previously owned Donzis -
    1996 22' Classic, 502Mag Bravo
    1987 20' Minx, 350Mag Alpha
    1975 18' Classic, 350Chevy Volvo 280

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Posting Permissions

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