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  1. #1

    Default yamaha 150 txr 2stroke

    Can not get WOT without motor surging over 4100 rpm. runs good at 4000 or lower rpm. Sounds like it is hitting the rev limitter, this should not be at 4300rpm . problem started day after over heat warning set off with flusher in yard. busser does not come on when in water. starts good runs fine up to 4100rpm. what do you think? blazer66 to rodbolt.

  2. #2
    Supreme Mariner
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    Default Re: yamaha 150 txr 2stroke

    I think I need a full model number.
    if what you posted is the full model number its an 06 or newer carbed 2 stroke.
    if not it could be EFI or HPDI.
    no tech questions by PM, they wont get answered.
    you have to be trusted by the people that you lie to .

  3. #3

    Default Re: yamaha 150 txr 2stroke

    Yes It is a 2006 2stroke carbureator V6 Yamaha S/N 6G4X 1018714 150TXR Note (NOT EFI or HPDI) Does have 6 ign coils, CPS, and CDI box oil injection and diagnostic harness connector at the oil level sensor harness for retreiving flash codes.

  4. #4
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    Default Re: yamaha 150 txr 2stroke

    check fuel system for restrictions, change both lift pumps clean all the carbs.
    problem will most likly vanish.
    no tech questions by PM, they wont get answered.
    you have to be trusted by the people that you lie to .

  5. #5

    Default Re: yamaha 150 txr 2stroke

    Is it possible that the crank sensor may be changing the timming to reduce RPM? Or thermo switch doing the same ? With motor at 4000 RPM increase rpm only makes motor start to surge instantly!!! Primer bulb is still tight when pumped at this rpm. Filter at motor new,10 micron 1quart fuel /water saperator new. At one point while running at 4300 rpm surging, motor picked up to 5000 rpm for 20 seconds and decreased back to 4300rpm and surged.I stopped motor!! started up agin it would not turn over 2500rpm and would bog down if I increased throttle. After 2 mins. it came up on plane and ran at 4000rpm back to launch ramp. What next Yamaha mech.has cleaned carbs, 3 months ago, well He said he did I marked everything nut and bolt on motor to see if he removed any item for repair!!!!!!!! Who do you trust??

  6. #6
    Supreme Mariner
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    Default Re: yamaha 150 txr 2stroke

    CPS doesnt affect ign timing on that engine during normal running but does control spark and spark timing,in conjunction with pulser inputs from the 1 and 4 pulser coil, for #2 and 5 cylinders.lose it and you lose spark on 2 and 5.

    CTS only affects ign timing during cranking and warm up.
    lose it and you get no ECU timing advance for cold starts.
    lose 1and 4 or 3and6 pulsers and you will lose those two cylinders plus #2 and 5.
    your still describing fuel issues.
    no tech questions by PM, they wont get answered.
    you have to be trusted by the people that you lie to .

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