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  1. #1

    Join Date
    Aug 2018
    South Padre Island, TX

    Angry 2009 VX 1100 Half throttle only or else stalls HELP!

    I've been having this issue the past few times I've taken my ski out. I rebuilt it from a total junk pile. (took me a year).

    -2009 Yamaha VX Deluxe with SBT rebuilt motor
    -first 10 hrs was running great except the fuel pressure regulator was stuck so was apparently running 80 lbs fuel pressure and was getting an error code. (ran like a bat out of hell though)
    -Speed sensor was going out (erratic speeds showing, jumping from 5,80,30,3 while at constant wide open 55+)
    -properly flushed and oil level correct
    -4th time out ran fine starting off and then would begin to stall at wide open
    -I replaced the fuel regulator and cleaned all the injectors and changed the spark plugs and oil (no metal in filter or oil)
    -still runs fine on the hose and revs quick, idles smooth even in water
    -I ran with seat off, no change, installed an inline fuel pressure gauge and keeps a consistent 42 lbs even when it's starting to stall, voltage is good 13.2 at idle, 13.3 at half throttle, plugs look good (medium brown) removed air filter
    -NO ERROR codes now, but the speed sensor is just staying at constant 0

    would the speed sensor cause this issue? I've tried everything I can possibly think of. Any suggestions would be greatly appreciated. My children call him "Mr. Splashy" and I need this thing to splash! lol


  2. #2

    Join Date
    Apr 2015
    Wales, UK
    Speed sensor is a wheel in ride plate probably has a stone wedged in it common issue. Have you YDS 1.33 diagnostics package? $75 on eBay

    sounds like you might have a leak somewhere have you done a compression test? Could timing be out? Coils maybe?

  3. #3
    Hi. You say the oil level is ok. Just checking that it’s spot on. Loads of owners get caught out with the well known oil over fill issue. Happens when changing the oil. You can only get about 2 litres out the oil tank but the system holds over 4l. Some either put 4l in and over fill...or the other thing is when you check oil level when it’s cold and not been ran, the dip stick shows no oil and people add oil...over filling it.
    This then causes the poor running, clogged oily air filter or worse. Just checking you already know about this issue. Internet is full of it.
    Other issue is the MR1 engines tendency to go through plugs really quickly. All the best.

  4. #4
    Myself's Avatar
    Join Date
    May 2007
    North Central Arkansas
    Also, just because the plugs look good doesn't mean they are. Ohm them out.

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