Any Jetski/2 Stroke Engine Wizards About??

Discussion in 'Tech/Mech General' started by dazzer, Jun 1, 2011.

  1. dazzer

    dazzer Read Only Funster

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    Hoping there is someone on here with more brains than ive got!! (Not a difficult thing :Rofl1::Rofl1:)

    Ive recently got a Kawasaki 750sx stand up jetski :Eeek: Got it given by a relative who was emigrating to Oz so it stood me at £0.00:BigGrin:

    He couldnt get it to run for more than a few seconds and gave up with it so I have inherited the problem.

    I know the problem is with the ignition side of things. When the plugs are out you crank the engine and get a good strong spark for about 2 seconds then nothing.

    Up to now ive replaced the following

    New battery
    New coil and HT leads and plug caps
    New Plugs
    Replacement CDI module that i removed from the same model of jetski and saw running before it was removed so i know its a goodun!!
    New stator/magneto assembly

    I think that pretty much covers every part of the ignition system!! :Doh: That little lot stands me at about £400.00 so its still a cheap ski as they seem to sell for about £1000.00

    Anyway changed all of that lot and ive still got exactly the same problem, its totally flumexed me and i am now at the point where im not sure what to do next (apart from take it to the local boat yard and leave em to it, but its now become a battle of wills between me and the bloody engine!!! and i intend to win :Rofl1::Rofl1:)

    If I try to start the engine it will kick into life straight away and run for about 2 seconds then die (same thing i get with the plugs out).

    Anyone out there got any ideas what i might be missing?? Ive cleaned out the petrol tank and put new fuel/oil mixture in it, but im 99% positive the problem is with the ignition side.

    All suggestions gratefully received as always :thumb::thumb:
     
  2. acting_strange

    acting_strange

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    It could be a broken wire on the ignition side that is arcing on the initial start then cant jump the gap when it overheats (as it will).

    Check the wiring with a good meter...
     
  3. Simannjo

    Simannjo Read Only Funster

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    Sounds more like an issue with some sort of safety feature...
    An immobiliser works in a similar way by allowing the ECU to run the engine for a second or 2 until the key code can be confirmed.

    Dont know what sort of safety feature but thinking along the lines of the cord if the driver falls off or a sensor if the fuel is contaminated with water.

    Summat else to think about...:Smile:
     
  4. dazzer

    dazzer Read Only Funster

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    In replacing the parts listed ive also replaced every single wire used on the ski with the exception of the stop/start button on the handlebars. I will bypass the stop button tomorrow to make sure its not that.

    There is no immobilser of any sort fitted to the machine and no sensor in the fuel tank (which ive cleaned and put new fuel in anyway.:Wink:)

    Thanks for the info, i never thought about checking the stop/start buttons but will let you know how it goes. :thumb::thumb:
     
  5. American Dream

    American Dream Read Only Funster

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    Hi Dazzer

    You mention a Start/Stop Button.

    Isn't there an emergency cutout that attaches to the rider so if/when he departs from the ski, it cuts the engine?

    Steve.

    Does the supply to the cdi module die at the same time the spark stops..

    Are you 100% sure it's not fuel supply problems?
     
  6. dazzer

    dazzer Read Only Funster

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    The stand up skis dont have the lanyard cut out thingy. They have a automatic circle return idea that doesnt work so everyone simply turns the tick over down so the engine stops when the throttle is released.

    Will check the power supply to the cdi module when cranking later today. :BigGrin:

    Im sure its not a fuel problem, its defo on the ignition side of things :Sad:
     
  7. combi

    combi Read Only Funster

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    My son rides trial bikes and it is very common on these bikes for the kill switch to cause problems.
    Worth trying.

    cakeboy
     
  8. wivvy's dad

    wivvy's dad Read Only Funster

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    Old mechanics saying.....

    "If it seems like a fuel problem, it must be electrics"

    And vice-versa.

    Check diaphragms on carb(s) etc etc
     
  9. Geo

    Geo Trader - Funster

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    Jet Ski basics
    1.Fuel
    2.Spark
    3,Water

    This may seem like a really silly suggestion
    After many hrs of trying to start an old Volvo Penta outboard it was pointed out to me it had to be in "WATER":Doh:
    Sensor in the tail shaft detected water and hey presto:thumb:
     
  10. mowbotman

    mowbotman Funster

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    jet ski

    what have you set the air gap to between the coil and the flywheel .
     
  11. pappajohn

    pappajohn Funster Life Member

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    do you know the exact year ?

    is it twin carb or single carb ?

    '95 onwards have twin carbs and oil injection.

    if its later than this the oil/petrol pre-mix AND the oil injection system may be over doing the lube side and oiling the plugs
     
  12. dazzer

    dazzer Read Only Funster

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    Jetskis run out of water as long as they are connected to a hose pipe to cool the engine when it runs.

    The flywheel space etc is factory set and none adjustable. The engine management box takes care of all that.

    Its a 94 single carb with the oil tank removed and premixed fuel used at all time.

    However, i think ive found the problem :thumb::thumb:

    I dig a little deeper with the stop/start switch and when i disconnected it the engine started and kept running :thumb::thumb::BigGrin:

    Re-connect it and the same problem occurs. Ive had a meter on it and cant find a problem with the switches but after a little digging i scraped the insulation off the wires and found the copper wire very corroded and black along almost the full length of the cable runs :Sad:. Looks like ive got a bit of a rewire job to do on the switch at the weekend :cry:.

    Will let you all know how it goes and thanks for pointing me in the right direction :thumb:

    Anyone want to buy some slightly used ignition parts for a Kawasaki 750SX jetski??? :Rofl1::Rofl1:
     
  13. pappajohn

    pappajohn Funster Life Member

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    i reckon you've got it there dazzer.....
    black wire is a common problem with wires susceptible to a corrosive atmosphere.

    usually only affects the return/negative wire so i suspect the lanyard switch will be a switched earth from the ignition circuit...pull the plug and ignition live goes to earth.

    i had it a few times on RC aircraft battery leads....as i said...only on the neg/earth wire.

    doesn't matter how much you scrape it, the wire remains oxidised and must be replaced.
     
  14. American Dream

    American Dream Read Only Funster

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  15. dazzer

    dazzer Read Only Funster

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    Your a man who knows your black wire!! Ive had a look at both wires to the kill switch and they are both very corroded inside. The start wiring seems to be ok so ive got 2 wires to replace tomorrow. Hope it dont take to long as the sun is shining and its high tide at 2.00pm tomorrow!!!

    Thanks for all your help :thumb::thumb::thumb:
     
  16. dazzer

    dazzer Read Only Funster

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    Just a quick update on this one.

    Replaced the wires (took a bit longer then planned as she who must be obeyed decided it was time to decorate the hall, stairs and landing :Doh:) and it started 1st crank and stayed running :thumb::thumb:.

    Sounded a bit rough so i gave the carb a good fettling and it now purrs like a pussycat :thumb:. Just need the wind to die down a bit (fingers crossed for tomorrow :Doh:) to go and take it for a blast in the sea. :thumb::thumb:

    Ill let you know how we get on...assuming the weather co-operates :Rofl1::Rofl1:

    Thanks for all your help guys :thumb::thumb:
     
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