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  1. #1
    Member
    Join Date
    Aug 2009
    Location
    Marsh harbour
    Posts
    1

    Yamaha 300 HPDI engine problems- HELP!!

    I have a Regulator in the Bahamas fitted with twin 2004 Yamaha 300 HPDI which has been running fine until now, 540 hours both engines.

    a problem has just developed with 1 engine.

    will not idle out of gear and stalls, belches smoke when first started, 20% down on engine revs and power for same throttle as other engine, and consuming 30% more gas than other engine at identical RPM.

    plugs changed with no effect.

    yamaha dealer and technician cannot identify any fault, even with Yamaha diagnostic tools!!

    anyone had a similar problem, and what was the cause??

  2.  
  3. Member
    Join Date
    Aug 2008
    Location
    Lorain
    Posts
    201
    #2

    Re: Yamaha 300 HPDI engine problems- HELP!! (Exodus)

    Unless already done I would start with a compression test. Was that done? I would think a tech would have done that but you did not mention if it was checked.

  4. Member
    Join Date
    Nov 2005
    Location
    Prairieville, Louisiana / Zolfo Springs, Florida
    Posts
    4,409
    #3

    Re: Yamaha 300 HPDI engine problems- HELP!! (Exodus)

    Also need to start checking filters and connect a pressure gauge to the top of the VST and see what kind of pressure you have at the medium pressure fuel pump,


    I HAVE BEEN OVER 80 AT LEAST ONCE!


  5. Member
    Join Date
    Oct 2006
    Location
    Hollywood
    Posts
    64
    #4

    Re: Yamaha 300 HPDI engine problems- HELP!! (Exodus)

    There was an update on the "TPS Sensor" to raise the voltage from .55 to .58. My motors were stalling at start-up and then when this update was done (a month ago) the stalling stopped. I can't answer the question about your fuel consumption however....

  6. Member
    Join Date
    Sep 2004
    Location
    Launceston
    Posts
    225
    #5

    Re: Yamaha 300 HPDI engine problems- HELP!! (Special K III)

    Follow the sticky for your low pressure fuel pumps. They will cause excess fuel consumption, smoke and a blown engine... It is a quick check and I'd do it before using it again

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