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  1. #1

    Default 1970 7.5 fuel consumption?

    Hello,
    I am wondering how much fuel consumption I can expect on my 1980 Johnson 7.5 seahorse under normal operation and weight? Model number is J8RCSS.
    I am either going to buy a 3 or 6 gallon tank and I am considering my options for a full day at the lake. its a 1980 not a 1970
    Last edited by tireland; 10-02-2017 at 01:50 AM.

  2. #2
    Join Date
    Feb 2001
    Location
    Central West Florida
    Posts
    14,151

    Default Re: 1970 7.5 fuel consumption?

    Whatever capacity tank you have with the engine, buy a identical one. No matter how far you travel, you'll have enough fuel to get back..... Maybe!
    We occasionally have questions. If you fail to answer, it may affect ours.

  3. #3
    Join Date
    Nov 2005
    Location
    Mt. Zion, Illinois,
    Posts
    528

    Default Re: 1970 7.5 fuel consumption?

    I have a '79 Evinrude 9.9HP. We used it this summer on a lake that measures 2.5 miles X 5 miles pushing a 16' aluminum boat plus people/gear. I had both 3 gallon and 6 gallon tanks. We easily ran for 3 days on the 6 gallon tank until it got about down to about 1/4 tank. Granted that was a lot of run to fishing spot and not start again for an hour or longer, but it was a few long runs each day with some slow trolling thrown in too.

    KJ

  4. #4
    Join Date
    Apr 2010
    Posts
    3,696

    Default Re: 1970 7.5 fuel consumption?

    The old rule is, 10% of the horse power at WOT. 7.5 horsepower equals 7.5 gal per hour.

  5. #5
    Join Date
    May 2014
    Location
    Reno
    Posts
    256

    Default Re: 1970 7.5 fuel consumption?

    I have to check your math for you. .75 Gal per hour for a 7.5 and that sounds right.
    84 Beachcraft 3.8 229cid 6681735 R drive6683545

  6. #6

    Default Re: 1970 7.5 fuel consumption?

    I have a 1984 8 hp and the fuel it uses in nil. I think the smaller tank is more than enough

  7. #7
    Join Date
    Apr 2010
    Posts
    3,696

    Default Re: 1970 7.5 fuel consumption?

    Thanks for the correction. Just wasn't thinking. Brain fart.

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