Cummins Marine Diesel Repower Specialists › Forums › Cummins Marine Engines › Different fuel burn rates on twin Cummins QSB 5.9 480hp

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  • October 24, 2023 at 1:17 am #155747

    Rob Freeman
    Participant
    Vessel Name: MYTH
    Engines: Cummins QSB 5.9 480hp x 2
    Location: Sydney
    Country: Australia

    Hi there.  I recently bought a 2001 Topaz 32 Express in Australia. It has twin 2012 Cummins QSB 5.9 480hp.  The boat runs great and been very reliable so far but I notice the starboard motor burns 10% more fuel than port.  Could this be a prop or alignment issue or something with the engine?  Thanks Rob 

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  • October 25, 2023 at 5:10 am #155772

    lpmcc
    Participant

    Also to note, the gear ratios in the trans might be different port to strb.  One might be running in “reverse” to go forward and the reverse ratio could be slightly different than forward.

    October 24, 2023 at 5:13 pm #155769

    Clark Leighs
    Participant

    No two engines will burn exactly the same fuel quantity.     If one prop has a tweak the other does not have  it will burn some extra fuel.  If the boat lists due to extra weight on one side than the other it may take some extra fuel.    Just some suggestions.   Others will have other suggestions.

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