2006 90 Mercury boat. Will crank but won t start?

Me and my father in-law went out fishing in his boat that has a rebuilt engine. Ran beautifully and were out on the water for 8 hours. He had taken his son out days prior and had no issues. We had just replaced the 3 prop to a 4 prop (measurements were exact). We were coming back to recover the boat and we had to wait for other people to launch before our turn. Only took around 10-12 minutes while we sat there with the boat idling. We brought the boat close to shore and I held it there with the engine turned off while he got the truck. He got back on the boat and tried to start it and we got nothing. It would crank but would not fire up. Manually recovered the boat and drove home. He suspected the engine to be flooded. Waited the next day and it still wont start. He checked the spark plugs and they were clean. Fully charged the battery and has a full tank of fresh gas with the required mixture of marine oil. Any help or suggestions?

9 Answers

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  • M.
    Lv 7
    5 months ago

    Is there fuel pressure?

  • 5 months ago

    Get a replacement

  • zipper
    Lv 6
    5 months ago

    Clogged fuel filter, bad fuel pump, {I hope not: JUMPED TIMING!} Weak coil or crack distributor!

  • fuzzy
    Lv 6
    5 months ago

    A short squirt of Aerostart or Start ya Bastard into the air inlet & try again. If it fires up even briefly you have a fuel problem if it doesn't you have an ignition problem.Take it from there

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  • CB
    Lv 7
    5 months ago

    You can check for fueling issue by opening the bowl on the carbs to see if they have fuel (unless it is EFI) or spray some starting fluid in the intake and see if it start for a second or two (if so no fuel to the plugs) if the plugs were clean after trying to start it a couple times you are not getting fuel too. They would be wet with unburned fuel if it was an ignition problem.

  • 5 months ago

    You ran the fuel tank down to the dregs, now the line or filter are clogged with tank crap. Even fresh fuel will not solve that. Check those items and the carb float and jets.

  • 5 months ago

    Could be a crank sensor or coil. Verty hard to say with modern ignition systems. We don't know what it looks like or how the system is controlled. Join a an owners forum for the make of boat.

  • Anonymous
    5 months ago

    Put a spark plug tester on the plug to see if HT is there. See link.

  • Anonymous
    5 months ago

    It's either a spark issue or a fuel issue. Thoroughly troubleshoot both systems.

    Grammar lesson - It should be "My father and I", not :Me and my father". You wouldn't say "Me went out fishing" would you? Of course you wouldn't. The same applies when you are talking about yourself and another person. It's You and I. He and I. She and I. My father and I. The grammar police and I. Got it? Good. Rise above yourself and don't screw it up any more.

    • M.
      Lv 7
      5 months agoReport

      If there is no spark, then you need an electrical diagram of the ignition system. Is this an outboard motor?

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