1999 Yamaha Outboard

Discussion in 'Outboard Maintenance' started by restlesswoodie, Jun 23, 2015.

  1. restlesswoodie

    restlesswoodie I Love microskiff.com!

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    Still having issues with my outboard. At wide open throttle the motor will bog down and almost feels like it's knocking and trying to get back to full throttle. Anything less than wide open throttle and it runs fine. I'm not sure if it's fuel starvation from the tank to the motor or in the carbs. When it happens, I can let it sit for a minute, choke it and play with it and it will run fine again until I hit full throttle. Any ideas?
     

  2. timemachine

    timemachine I Love microskiff.com!

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    The first thing I ever look at is if the fuel line into the motor is sucking in air, and it is not always that easy to tell.

    Next up would be clogged filter, or the little pump.

    if you have a small plastic tank, you could try closing the vent, moving the tank up onto the seat, and sitting on it to make some pressure.
     
  3. restlesswoodie

    restlesswoodie I Love microskiff.com!

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    I've replaced the fuel lines with 3/8" marine grade hose, replaced the water filter, replaced the primer bulb and connection to the motor. Still bogging down.

    I'm assuming it is carb related now and they need cleaned/rebuilt. Has anyone ever heard of running a small amount of gas in a separate tank with a heavy mix of sea foam or like product to really hit the carbs with a cleaner without dismantling carbs?
     
  4. erikb85

    erikb85 I Love microskiff.com!

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    Bandaid fix really. If theres something plugging a jet, seafoam isnt gonna pick it up amd move it out of the way. Im leery of those products on boat motors.
     
  5. timemachine

    timemachine I Love microskiff.com!

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    Plus, those carbs are made to be easy to clean. Last year I bought a 50 yamahaw that had been unused for 20 years. Needless to say, the carbs had som residue in them, but I had the motor running fine in a couple of hours.
     
  6. blackmagic1

    blackmagic1 I Love microskiff.com!

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    sounds like my '00 C60 when the overheating self preservation kicks in....which ended up just being a problem with my thermostat. Used to happen ALL the time until I replaced the thermostat. Take it out and look how goobered up it is.
     
  7. DuckNut

    DuckNut Brandon, FL

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    Pintail, is the motor missing, skipping or anything like that or is it just seem a little sluggish with a little extra knocking noise?
     
  8. priscillatgorilla

    priscillatgorilla I Love microskiff.com!

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    you're a wise man !

    seafoam or any other pour in the tank product will NOT repair a carb problem - carb(s) will require removal,dissassembly and cleaning - anything else isn't going to cut it...

    companies are making a fortune from products like seafoam,startron,motor medic,etc....