Wont start

Discussion in 'Powerboats' started by Days away, Jul 26, 2009.

  1. Days away
    Joined: Jul 2009
    Posts: 2
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    Location: Elsinore,Utah

    Days away New Member

    Just bought a murcruiser 302 with a 888 outdrive.
    It will start it backfire and pops through the carb.I have not done a compression check yet .
    I have checked the firing order and so forth though.ANY OTHER IDEAS.?????
  2. Fanie
    Joined: Oct 2007
    Posts: 4,603
    Likes: 170, Points: 63, Legacy Rep: 2484
    Location: Colonial "Sick Africa"

    Fanie Fanie

    Make sure the ignition timing is right. If this is out the firing is done out of sink with the cylinders and the motor won't run.

    If the firing timing is correct then there can only be only two things, fuel and spark. If there is fuel and spark it must go.
  3. Days away
    Joined: Jul 2009
    Posts: 2
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Elsinore,Utah

    Days away New Member

    Wrong firing order

    I was doing the wrong firing order come to find out it is a 5.0L HO.Thanks anyway.Sherman
  4. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Clearly there is fuel and spark Fanie, otherwise it wouldn't be back firing!

    It sounds like it could be one a several things, but more detailed information is necessary and a procedural diagnosis begun. It's likely a fuel delivery issue such as a stuck needle or float, from gum or varnish.

    How long since it's been running normally? Is this a sudden departure from normal or have things been slowly getting worse until now? How old is the fuel? The fuel filters? Water separators? Any leaks?

    In all honesty, a mechanic can take a quick look and figure out what issue(s) you engine has in a just a few minutes. A few simple tests or checks and he'll be ready to order parts. It would be a wise investment to get a repair manual for you engine/drive combination (at the very least) if you expect to do any real service on your boat.
  5. CDK
    Joined: Aug 2007
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    Location: Adriatic sea

    CDK retired engineer

    The most logical explanation for an engine to backfire is that the mixture is too lean. One or more jets clogged, sediment in the carb etc., quite normal for engines that have been out of service a long time.
  6. gonzo
    Joined: Aug 2002
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    Location: Milwaukee, WI

    gonzo Senior Member

    The 302 and the 5.0 are the same engine. Make sure you are timing it like a Ford and not a GM. I have seen that a lot and it will backfire like you say. 1-4 cylinders on left bank.

  7. Frosty

    Frosty Previous Member

    Gonzo means the rotation of the distributor is different, Ford-- GM.

    East to see way of rotation ,--its the way the rotor arm advances.
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