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  1. 9

    Yamaha 2-stroke 50HP 1980's bogs and not reaching max RPM

    how about not enough fuel to the air going in
  2. 9

    Yamaha 2-stroke 50HP 1980's bogs and not reaching max RPM

    have you tried cleaning the carbs? does it help to use the choke when the problem shows up? have you checked compression on all cylinders? restricted main jet or maybe something floating around in the carbs plugging things up. even water down in the bottom of bowls could cause problems from...
  3. 9

    70HP YAMAHA 1990 only runs on 1/3 cylinders!

    not enough fuel due to plugged/restricted passages or a vacuum leak. something is not letting getting the proper fuel to air ratio into the 1 & 3 cylinders. heated sonic cleaning machine helps when the carbs are taken completely apart and soaked/ cleaned properly.
  4. 9

    Yahana 200hp txrr stumbles at idle

    in post #14 I asked if you linked all carbs with throttle plates completely closed. was that not part of the link and sync procedure?
  5. 9

    Low compression on top cylinder.

    I have done small heads myself at home before, but something the size you are dealing with may be best to take it to a shop to have it resurfaced.
  6. 9

    Low compression on top cylinder.

    no, the whole head needs to resurfaced until flat
  7. 9

    Yamaha 50 tlr prime start test

  8. 9

    Stumped, one cylinder seems dead

    make sure the key is in the slot on impellor and the impellor is not spinning (broke loose from the shaft collar) always buy the OEM pump kits and replace it all just to let you know I am a Backyardian that bought a Used Yamaha back in 2008 so I joined this site myself to figure out what I...
  9. 9

    2000 C40TLRY 40 hp 2 stroke

    buy, beg , borrow, or rent a timing light to see what the CDI is doing to the timing. I had a problem with mine when I got it in 2008, turns out I could not get the timing at idle to hit spec without messing with the WOT timing. so I bought a new CDI and that took care of the timing problem.
  10. 9

    Runs Well, Can’t Reach Top Speed??

    apparently, you have never worked on Yamahas. maybe the old johnyruds is what you are talking about moving the timing plate.but those were way back 30 or40 years ago
  11. 9

    Runs Well, Can’t Reach Top Speed??

    on all 2 stroke motors I have ever worked on ,outboard, chaisaw, weedeater etc there is a idle speed adustment srcew that cracks open the throttle plates to set the idle speed. just like on my C40TLRX shown in the pic I posted there is a spec for timing while at idle, and you do not change the...
  12. 9

    Runs Well, Can’t Reach Top Speed??

    so are you trying to say full retarded spec is not with throttle at idle?
  13. 9

    2008 90TRL need more power!

    Are you sure the RPM and speed are low? Make sure your tach is set up properly for your motor, I would think you could tell if the motor was winding up to 5500 or not can you get speed from a GPS? Not sure if a smart phone app might do that
  14. 9

    Runs Well, Can’t Reach Top Speed??

    then what would you call this? seems to me with the throttle at idle the timing is full retarded and the timing advances to full advanced as you open up the throttle. But this is on my C40 not the OPs motor
  15. 9

    Runs Well, Can’t Reach Top Speed??

    never heard of a motor without an idle timing spec. motors need to have timing set for start and idling and timing advanced to a set timing for them to run properly at higher RPM
  16. 9

    engine stalls past 4000 rpm Suzuki DF175

    testing is needed, not just throwing parts at it and hoping. rail pressure would be a good start. but the collapsing bulb did indicate a restriction on the fuel system. did you get that stopped?
  17. 9

    2000 C40TLRY 40 hp 2 stroke

    did you drain the carb bowls after running the fuel out before putting away? running until motor dies still leaves fuel in the bowls, then the gas evaperates, but leaves oil and gas residue in there that will plug up jets/passages. This motor does not have a choke, At start up the prime start...
  18. 9

    Runs Well, Can’t Reach Top Speed??

    did you check with a timing light to make sure idle and WOT timing are both in spec?
  19. 9

    Runs Well, Can’t Reach Top Speed??

    has the motor ever pushed the boat like you want it too? maybe it is just too small of a motor, or it is propped wrong for the load it is trying to push.
  20. 9

    2000 C40TLRY 40 hp 2 stroke

    measuring peak voltages into and out of the CDI is the best way to see if it is working as it should. your service manual has all the specs. a timing light hooked up to the plug wires will show if timing is where it should be along with if there is current heading to the spark plugs. I lost...
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