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  1. #1

    2003 yamaha fx140 top speed..need help!

    Hey everyone, i am looking for some help, someone told me to come to this sight and it would be answered! :0

    Anyways, so my problem is...
    It will NOT reach any speed greater than 43MPH.

    On another forum, someone suggested taking out the air filter and seeing if it ran faster/reved higher. Before i took this out and tested the ski, it would only rev to 7-8,000 RPM.
    After i removed the filter it is reving at 10,000 RPM now but it wont go past the 43MPH.(before air filter removal, it would go 38MPH)

    Anyways, i am ordering a new filter, and i did change the oil today but did not get to test the top speed if it changed at all from oil.
    Also, should i check the spark plug gaps? i put new ones in but forgot to test the gap.


    Before i rode the ski this year i had to buy new housing (i guess it's called) that goes around the impeller, or the thing that turns in the water (not sure haha) and a rubber belt like thing came off the turn part of the ski (in the back) not sure if that has anything to do with the top speed though, runs perfectly just not top speed.

    I also was thinking it could be something in the gas because it hasn't been rode in a LONG time and old gas was in it.


    The ski has 65 hours on it, and it has never had an impeller changed but it looks to be ALRIGHT



    Any help/things i can try to achieve max speed? I think the top speed should be around 55MPH so i am about 10 short.


    Thanks so much!


  2. #2
    Boilerman Bill BPnta's Avatar
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    Your RPMs are fine and your speed is down. Sounds like a problem with the pump/hull.

    Since the the liner's been replaced already I would pull it apart and inspect the impeller/stator/nozzle as well.

  3. #3
    Quote Originally Posted by BPnta View Post
    Your RPMs are fine and your speed is down. Sounds like a problem with the pump/hull.

    Since the the liner's been replaced already I would pull it apart and inspect the impeller/stator/nozzle as well.
    Okay and well i havnt changed the impeller EVER so that might be why but what is the stator and nozzle?

    Thanks!

  4. #4
    Addicted Member 5001craig's Avatar
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    Welcome to the forum!

    Quote Originally Posted by yamahaa View Post
    Okay and well i havnt changed the impeller EVER so that might be why but what is the stator and nozzle?

    Thanks!
    The stator (also called the impeller duct) is directly behind the impeller and directs the somewhat spinning water flow from the impeller straight back. A stator has veins and these veins are what straightens-out the water flow.

    The nozzle is directly behind the stator and squeezes the water back down after going through the larger diameter stator. There is also a steering nozzle behind the stator/nozzle assy.

    I would guess it's in the pump. Do you hear (or feel) any noises or vibrations that are different? I would pull the pump and spin the shaft to see or feel if the bearings are bad. If they are, I would bet you will be able to feel and possibly hear them when turning by hand with speed being down.

    You may even just have something caught between the prop and the liner. The drive shaft goes through an intermediate bearing at the hull and this requires lubrication. I've heard of these going bad.

  5. #5
    Quote Originally Posted by 5001craig View Post
    Welcome to the forum!



    The stator (also called the impeller duct) is directly behind the impeller and directs the somewhat spinning water flow from the impeller straight back. A stator has veins and these veins are what straightens-out the water flow.

    The nozzle is directly behind the stator and squeezes the water back down after going through the larger diameter stator. There is also a steering nozzle behind the stator/nozzle assy.

    I would guess it's in the pump. Do you hear (or feel) any noises or vibrations that are different? I would pull the pump and spin the shaft to see or feel if the bearings are bad. If they are, I would bet you will be able to feel and possibly hear them when turning by hand with speed being down.

    You may even just have something caught between the prop and the liner. The drive shaft goes through an intermediate bearing at the hull and this requires lubrication. I've heard of these going bad.
    I dont hear any vibrations or feel them. Unless its full throttle

    what should i do?

  6. #6
    Addicted Member 5001craig's Avatar
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    I'd pull the pump and have a look-see at what's inside.

  7. #7
    Quote Originally Posted by 5001craig View Post
    I'd pull the pump and have a look-see at what's inside.
    Okay thanks, and just to make sure... the pump is the big tank thing that is in the battery compartment(back seat)

  8. #8
    The pump is located in the cavity you are referring to but is accessed from behind and underneath the ski. It requires some skill and experience to remove and inspect and there are some very good threads on this site showing how to do it. I am guessing that your experience level may not be up to the challenge but You can crawl underneath the ski, unbolt the intake grate and shine a light inside the tunnel to see if the impeller is banged up or if there is a significant gap between it and the housing. If the impeller blades are dinged up or you see an uneven amount of gap between the blades. By your explanation, I don't know if you had the impeller replaced or the housing around it. You may want to post that you could use some live help in your area. If you are in an area where others are, they might be able to coach you on the next move. You now have the rpms in the right range, don't worry about the plugs unless you dropped them. If the fuel is old, then either siphon it out or dilute it with fresh but again if the rpms are there, you should be able to burn it up. Your only other alternative is to pay a shop to diagnose the issue but someone should be able to help you from the forum. Good luck.

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