Yami Kicker Problem

Discussion in 'Boats, Motors, Trailers and Towing Rigs Forum' started by Rockfish, Aug 22, 2013.

  1. Rockfish

    Rockfish Well-Known Member

    A New problem with my older Yami 9.9 HT kicker. It starts up easily but runs rough and produces little power and I think is running on one cylinder. Once it warms up a bit it seems to kick in and both cylinders run and it will run perfectly from that point on. Sometimes stopping it and restarting after it is warmed up a bit will get it to start running correctly. If left on its own it is like a switch when it kicks in and instantly has lots of power and runs great. It seems to be getting a little worse with time in that is taking longer and a little more difficult to get it to kick in, smooth out and develop full power. Anyone else had this happen or have any ideas? Could this be electrical?
    Last edited by a moderator: Aug 22, 2013
  2. spring fever

    spring fever Well-Known Member

    Check your plugs and leads. Try and isolate the cylinder it is running on. Switch plugs.
  3. Rockfish

    Rockfish Well-Known Member

    The plugs were new at the start of the season but the leads are old. I guess new plugs and leads are a good low cost place to start.
  4. scott craven

    scott craven Well-Known Member

    It may need a new brain....:confused:
    buddy of mine had intermitent problems similar to yours.
    did everything to try and solve it , and ultimately the computer
    chip was replaced and it ran like new again.
  5. Kokanee

    Kokanee Member

    my 8 hp high thrust gave some grief last year turned out to the choke sticking on when I used the electric choke on the key switch
  6. profisher

    profisher Well-Known Member

    Check your oil level and make sure it is not overfilling. If it is then its either the fuel pump diaphragm or the thermostat. I have only had one power pack go on all the Yami kickers I've owned. The symptoms of that one were it would not hold a steady rpm, it was all over the map. I think the computer wasn't holding the engine timing in sinc. Could also be a partially blocked jet in the carb...do you have good inline fuel/water separating filters installed?
  7. Rockfish

    Rockfish Well-Known Member

    Not a problem with fuel. The kicker has its own fuel line and racor filter/water separator from the main fuel tank and is a hard connect to the kicker not a plug in. Has a new fuel pump that is the upgraded water cooled type and a new thermostat and is not making oil. By the way making oil can also be caused by Carb Problems not just the fuel pump or the themostat as was the case with this motor previously. Could try another T stat as we have a new spare.

    The motor runs flawlessly once it gets going except for a period when first started when it is cranky and lacks any power. Once running for a bit and it starts to run correctly there are no problems with it at all and it will run all day perfectly. Whatever is causing the problem at start up goes away after a while, possibly related to warming up or an electrical problem.

    I know problems with the enrichment circuit are rare but could that be a problem on start up?

    The problem does seem to be getting a little worse over time and I am concerned that one day it is just going to stay in poor running/no power mode and not start running correctly after a few minutes. This is new and the motor has been running perfectly all summer up to this new problem developing.

    When it starts running correctly it is instant like something clicks in or out, not a gradual improvement.

    Have added some injector cleaner from the Merc dealer to the gas tank for the big two stroke and the instructions say it will also clean carbs.
    Last edited by a moderator: Aug 23, 2013
  8. lazylump

    lazylump Member

  9. Rockfish

    Rockfish Well-Known Member

    Talked with my Yami Mechnic. He will lend us a loner power module (brain) to test to see if this solves the problem if necessary and I will get one of my friends to put it in to test (couple of bolts and some color coded wires). No point in buying a new one for $300. or a used one for $150. if we don’t need it. He did tell me he has had them where if you press in on the side of it with a finger the motor runs fine but messes up as soon as you remove your finger pressure.

    He thinks it is more likely electrical or carb because if the brain is gone it would most likely not run at all or have intermittent problems and would not run perfectly all day as mine does once it kicks in.

    Will start with new plugs and leads. The leads are ancient and likely original. Then give the cleaner added to the gas a chance to work.
  10. MonkeyWrench

    MonkeyWrench Member

    I've worked at a Yamaha dealership for 6 years, i have never replaced a CDI box on one of these motors. Can you provide me with a model number of your outboard? usually found on the port side of the transom bracket.

    If you want to confirm that the engine is in fact only running on one hole, while the engine is running, remove the spark plug lead on your top cylinder. Listen to the reaction of the motor, it should be a clear change, now put the spark plug lead back on and again listen for the change. You are essentially performing a cylinder drop test. Now repeat that process on the lower spark plug lead. Both cylinders should react the same. If not, the one that makes no change is the cylinder that is not working.

    Now when you are armed with that information, you have to determine why it's not working.

    The engine needs 3 things to run. Spark, Fuel, Compression.

    Because you have mentioned that the engine smartens up after a while we can rule out compression - that is an all or nothing problem.

    To rule out spark, simply pull the spark plug out of the motor, connect it to the spark plug lead and test it - hold the electrode (end of the plug) against the block of the motor - if you can find a clean bolt with no paint that is your best spot. Now crank the motor over and look for a spark. Keep in mind that Yamaha uses a very very weak spark even when brand new in the box so take a real good look before you determine there is no spark. If you don't find spark, then change the plug. Try again.

    Now, is when it get's fun.

    If you find that you don't have spark. Before you start swapping parts which will get very expensive very quickly, learn to test and eliminate components as potential problems. Start with the stator, work your way to the CDI box. All the voltage specs can be found online, and if you can't find them PM me and i'll look in a manual for you.

    Please note. 90% of all the issues I see on these motors is fuel related. Do the spark test, if you have something there, then remove the carb and clean it thoroughly.

    Hope this helps

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