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  1. #1
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    86’ Yamaha 150hp CDI/ Power Pack problem??

    I took my boat to a local reputable shop after I had some engine issues. I was told the CDI box was going bad (loosing spark on cylinders #2 and #5 above 2000 rpms). I ordered a new one from a shop in Arkansas and installed it on my motor. Took the boat out yesterday and it’s doing the exact same thing that it was prior to me replacing the CDI (sluggish out of the hole, top end was weak, and only turning 4500rpm max instead of the typical 5500 rpm). Do you guys have any idea what other problem I could have? I have questioned if the new CDI I ordered could be faulty or if that is even the problem since it didn’t change anything. Anything is appreciated. Thanks guys.
    1992 Champion 184 SC / 1986 Yamaha 150hp

  2. Member
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    May 2018
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    #2
    I went through the same issue a few months back, chased my tail quite a bit. Ended up being broken reed valve for me. I cleaned and rebuilt carbs a couple times. Adjusted timing. New fuel lines/primer bulb. I would verify you are indeed losing spark. I used a timing light clamped to each plug wire to verify. In my research a majority of the time older Yamaha lose power/rpm, it’s a fuel starvation problem.

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    #3
    What model motor do you have? I’ve been thinking it could be a possible fuel problem.
    1992 Champion 184 SC / 1986 Yamaha 150hp

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    May 2018
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    #4
    I have a ‘97 pro-v 150. Carb cleaning isn’t bad, just a little time consuming. If it hasn’t been done in awhile it would be worth doing just for piece of mind. Primer bulb should stay firm while running, if it feels soft and engine seems to run better when pumping the bulb that could be your problem. Check fuel filter for debris. Older fuel lines weren’t designed with ethanol in mind, and break down when running fuels with ethanol. I wouldn’t run the motor wide open until you think you’ve solved the problem, if it does end up being caused by a lean fuel condition you could burn a piston up. I found my problem by chance, while running the motor without the intake cover on, I noticed fuel spitting out of the intake of one of the carbs. Fuel system is pretty simple I would check each component individually starting at the fuel tank. After you’ve ruled that out than move on to ignition system. If you google Yamaha outboard power loss or rpm loss you’ll find a lot threads with your symptoms

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    #5
    Alrighty. Appreciate the information sir. I’m gonna try to work on it a little bit tonight/ tomorrow. We’ll see what happens! Thanks again!
    1992 Champion 184 SC / 1986 Yamaha 150hp

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    Feb 2018
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    #6
    The vast vast majority of Yamaha owner's that buy a CDI have a perfectly good working spare part.

  7. Member
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    Nov 2018
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    #7
    Yam911, can you elaborate for me? Are you trying to say that the CDI’s usually aren’t a problem?
    1992 Champion 184 SC / 1986 Yamaha 150hp

  8. Member
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    Nov 2018
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    #8
    Hey guys, just thought I would let you all know what the outcome was. It ended up being the trigger coil. Changed it out and she’s as good as new now.
    1992 Champion 184 SC / 1986 Yamaha 150hp

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    Melbourne FL
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    #9
    BQ thanks for the info

  10. Member
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    Dec 2015
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    Whitesburg, KY
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    129
    #10
    Crank trigger was doing that on my engine