15 HP merc bogging down when throttled

Discussion in 'Outboard Maintenance' started by bray824, Aug 7, 2011.

  1. bray824

    bray824 I Love microskiff.com!

    Wondering if you guys could give a little advice. I just got a 2 stroke 15 hp merc 1999.

    The first test run it had an old fuel line and tank with no breather in the gas cap and it wouldn't idle right, and wouldn't run unless I pumped the primer ball but when it did get past the first 1/3 of throttle it would run great.

    I got a new tank, line, and gas and took it out today. It starts right up and idles great at low speeds. If I give it gas it wants to bog down and will shut down. Its like it doesn't get enough fuel at first. If I pull the choke on quick second and then give it gas it hops right on plane and takes off great.

    I don't know much about motors but it seems like its not getting enough suction or something like that. Once it starts going its fine. Any suggestions? Thanks.
  2. Brett

    Brett > PRO STAFF <

    1999 outboard, I'd start by doing a complete lube, tune-up and carb rebuild.
    Then see what that does to the performance.

  3. AfterHours2

    AfterHours2 Stripper in my own Mind!

    Carb kit, rebuild and new fuel pump should solve your problems.. Also, check your plugs and make sure each cylinder is firing correctly. Try spraying some sort of starting fluid in your carb throat to see if the engine picks up speed when bogging. If it does then it is surely a fuel issue..
  4. damarshall7

    damarshall7 I Love microskiff.com!

    Sounds like a clogged high speed jet, or a air leak somewhere in the fuel delivery system. Clean and rebuild carb, rebuild fuel pump and replace hoses. Make sure all of the hoses are clamped tightly and there is no where for air to leak in the system. I have ran into this with a few motors i have rebuilt. If you need any advice feel free to pm me
  5. bray824

    bray824 I Love microskiff.com!

    Rebuilt carb yesterday. Same problem. Adjusted idle screw on top of carb and problem seems to be fixed. I didn't think there could be any major problems as the motor looks and sounds perfect. Seems like it was just running too lean.
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