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  1. #1
    Petty Officer 3rd Class
    Join Date
    May 2010
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    Lewisville, TX
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    97

    Default Fuel consumption for a 1975 70HP Johnson?

    OK, took the Whaler out for sea trials yesterday (66 Whaler Sakonnet. The engine ran great through out the power band! I am a bit concerned about fuel usage. What is the average fuel burn at full throttle for this engine used on this type craft? I travelled about 12 miles total and burned about 4 gallons of fuel. This seems a bit high. I did rebuild the carbs on the motor. Any inputs or suggestions are appreciated.

    Jet Wrench
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  2. #2
    Petty Officer 2nd Class
    Join Date
    Apr 2010
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    167

    Default Re: Fuel consumption for a 1975 70HP Johnson?

    70 (2 cyl)
    5,250 rpm
    7.7 gal. per hour


    70 (3 cyl)
    5,500 rpm
    7.4 gal. per hour

  3. #3
    Petty Officer 3rd Class
    Join Date
    May 2010
    Location
    Lewisville, TX
    Posts
    97

    Default Re: Fuel consumption for a 1975 70HP Johnson?

    Thanks Johnson 89,

    I guess I'm not too far off the mark then. I will need to throttle back to get some decent fuel burn. I did set the carb floats per the manual. I don't see any leaks, but I see a bit of residual fuel at the bottom of the carbs. I was wondering if I should set the floats a bit lower than what is called out in the manual to alleviate this?

    Jet Wrench

  4. #4
    Moderator
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    Nov 2009
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    South west FL
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    11,053

    Default Re: Fuel consumption for a 1975 70HP Johnson?

    Hey Johnson89. What's a 70 hp 2 cyl and how come these mtrs burn more fuel at a lower rpm ?

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