Outboard Motor Repair Question

Discussion in 'Boats - RVs - Planes' started by Red Herring, Jun 24, 2005.

  1. Red Herring

    Red Herring

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    Hi All,

    My Yammy 9.9HT 4 stroke kicker is needing repair, and I was hoping someone might be able to point me in the right driection.

    It starts fine, but only runs on one cylinder, used to be that the second kicked in when it warmed up a little, but no longer. Plugs didn't look bad - and I've just put new ones in, I don't know the last time the valves were adjusted, but regular maintenance has been done, and compression (leak down) is good.

    Where should I start digging? I am thinking solonoid or valves... anyone have an idea?

    Thanks,

    Steve
     
    Last edited: Jun 24, 2005
  2. JRFJ4-

    JRFJ4-

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    Spark Plugs

    See if it's hitting on that cylinder. Or just replace plugs anyway. That's the first thing a mechanic will do. That's just routine.

    Always have a couple of sets of plugs for everthing. Lawnmowers, chainsaws, atvs and especially boats. Even the four strokes foul up plugs.


    Just my .02
    :cheers:
    J.R.
     
  3. Landpimp

    Landpimp GOLD Star

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    plug wires?

    I got the same motor.

    also a tip if you run it in saltwater, clean the little piss hole out.........if she plugs up the motor will overheat and shutdown(without doing damage)
     
  4. fsusteve

    fsusteve

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  5. White Shark

    White Shark

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    Not cleaning it after a single salt water run can plug up the cooling ports and hoses enough to starve the impeller, resulting in a future overheat. You can easily ruin an engine by not flushing it enough.

    Even though the plugs look good, I'd replace the wires and plugs anyway. If the second cylinder is supposed to kick in after warm up, I'd look into the triggering mechanism. Get the factory manual out and it should have some tech info to troubleshoot that issue. I'm still an old school 2 stroke outboard motor guy, but I've been lusting after some of those nice 4 strokes! Good luck and let us know what turns up.
     
  6. Red Herring

    Red Herring

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    Thanks guys... seems like I've got it. I started taking all the contacts apart, cleaning, lubing and replacing, cleaned the grounds, and checked the wire/cap contacts... and voila... so, not really sure which it was, but what the heck... runs fine now.

    As for salt... I run exclusively in it, and I never forget to FLUSH. I flush both engines, even if i have not run the little one... just to get the spray out. Thoroughly hose down the boat and motors as well.
     
  7. Capt. Jim

    Capt. Jim

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    If compression is good, make sure you have spark on that cylinder. If you have spark at idle, make sure you continue to have spark with increased RPM's. I have two big Yami's on my boat that drop 2 cylinders by design at idle.

    If there are identical coils on the engine, try swapping them and see if the same cylinder misses.

    I don't know what kind of fuel deliver system is on that particular engine, but make sure you have fuel delivery to that cylinder. Again, if there are any similar fuel parts on each cylynder, Try swapping them and see if the same cylinder will not fire.

    Make sure your timing is correct.

    Your engine may have a low-pressure oil pressure switch. If so make sure you have pressure and the switch is not defective. May shut down only one cylinder if insufficient oil pressure to allow you to put-put home.

    You most likely have one or more sealed electrical modules on that engine. These are difficult to check and expensive to buy and swap, as they are non-returnable. Always a possibilty.

    Lastly, corrosion is a big factor, especially if used in saltwater. Check/clean, if necessary, all wiring harness connectors.

    Good luck, and let us know what it was after you finally fix it.
     
  8. Capt. Jim

    Capt. Jim

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    Glad you got it fixed. Seems you posted while I was writing my post. :cheers:
     
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