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  1. #1
    HDFATB's Avatar
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    Gpr1200 runs fine then loses power and exhaust alarm sounds?

    need some expert advice GP1200R takes of fine will do 60 plus then at full throttle it will drop down between 30-40 and exhaust alarm will sound? I shut it down restart and it takes off fine I don't think its a fuel problem is it cavitation never saw this before
    Last edited by HDFATB; 06-10-2013 at 01:11 PM.


  2. #2

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    Welcome to the forum.

    Just a few things to consider:

    Your exhaust pipe, in order to function properly, must operate at a high temperature to enable exhaust scavegeing (ie make your engine more efficient). You have a plastic cover on the "stinger" part of the pipe from the factory to protect you from burning yourself due to the excess heat generated. The catalytic converter (cat con) must be exceptionally hot in order to burn all of the unburned oil from combustion. If the pipe is to cool, the cat con will plug and the boat will run like it has a potato stuck up the exhaust pipe.

    The temperature probe will alarm when ever the pipe fails to achieve that hot temp. The pipe can get cold if 1. You remove the cat con thus not allowing the pipe to heat up.
    2. The cat con has broken up internally and is still stuck in your pipe. Because parts remain in your exhaust pipe (the stinger to be exact), you will not be able to achieve a top end because your exhaust is partially plugged. It will run but it will run poorly. In both cases, your pipe cannot heat up and thus the alarm.

    If this is the case, then as a test you can take your boat out on the water and bounce the boat on waves to get the pieces of cat con to rattle around in the pipe. The pieces will rearrange themselves occasionally and your exhaust pipe will unplug, allowing exhaust gasses to flow and you will get your top end back. If this is all true, then you will have to remove the stinger as well as the exhaust muffler to remove all pieces of broken cat con. You will have to replace with a new cat con or a "D" plate.

    This is one of a few things that your problem could be. It does not cost anything to check. You could also just bypass all of the water testing and just remove the stinger and check to see that your cat con is still intact.

    Of course if you have a "D" plate installed now, then none of this is true.

  3. #3
    HDFATB's Avatar
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    thank you for the info

    I wasn't getting any replies so I did some research and saw a few people with the same problem so I called Riva and ordered a dplate, chip and a flow through exhaust.

    to tell you the truth I was thinking cat/con first but ruled it out because the dealer warned me if I didn't use Yamaha lube all the time it would clog my cat/con so I made sure that was the only oil I would use.

    its ridiculous that after 100 hours a $1200 oem part has to be replaced its great that there is a fix for under $200 and will give you better performance.

    thank you again for reply ill post the results after I test it out.

  4. #4

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    You were misinformed about the oil.

    Yamalube is an adequate oil. It is a semisynthetic oil that the cat con can burn efficiently. You can use the higher end fully synthetics like Amsoil or Klotz for a cleaner burn. Without the cat con, you will have more smoke from your boat. With the synthetics, considerably less smoke. Also, with the synthetics you will not have to clean your power valves near as often since these oils naturally burn cleaner.

    Without the cat con, you will lose about 50 rpms in your top end. Remember, that exhaust pipe was designed to operate at a higher temp which the cat con partially helps to create. You can get your rpms back if you dump some of the water (coming out of the head and going into the pipe) over the side. If you reduce the water which is used to cool the pipe, the pipe will heat back up closer to its designed operating temperature.

    Do some reading on this.

  5. +1 by:

    WFO

  6. #5
    HDFATB's Avatar
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    your right I defiantly have to do some reading I've had this ski for over ten years and I barely use it.

    to much work and to many hobbies!

    thanks again I'm glad I talked to you sound like you know your stuff now to find the time to fix this ski and test it!

  7. #6
    HDFATB's Avatar
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    put new dplate in today and chip the cat/con that I removed looked fine only took a hour to install.

    I knew it was to good to be true dropped it in water and it did the same thing punched it took right off went
    up to 7000 rpm hit 44 mph then bogged dropped down to 35mph about 3500rpm let off on throttle a 1/4 she picked back up to 7000rpm for about 30 seconds then bogged.

    the only difference this time was the exhaust alarm didn't go off because chip was installed. took her back to dock to flush and while I was flushing I pulled chip to see what would happen the alarm didn't go off so I shut her down without chip and restarted no alarm.

    LOST ANY IDEAS?

  8. #7
    Happily Self-Employed WFO's Avatar
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    fuel restriction somewhere

  9. #8
    HDFATB's Avatar
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    that's what I thought the first time but why was exhaust alarm going on?

  10. #9
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    lean exhaust can get hot... also cat may have been partially clogged... anyways now you have a d plate so carry on with the diagnosis

  11. #10
    HDFATB's Avatar
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    if its fuel filter or carb should I get 7000rpm one min and drop down to 3500 and back up again?

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