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  1. #1
    Join Date
    Sep 2019
    Location
    toronto
    Posts
    14

    Default How to check if speed is good on 20hp mariner outboard motor

    Hi all friend

    I have 14.4 foot boat with 20hp 2 stroke mariner outboard motor, how i can check the speed if based on 20hp,

    Recently i took boat after changing the trigger, for fishing and use my cellphone software for speed and got 11km/hr. is this ok or ahould be more... How i can check

    Thanks

  2. #2
    Join Date
    Sep 2003
    Location
    New Tripoli, PA, USA!
    Posts
    16,923

    Default Re: How to check if speed is good on 20hp mariner outboard motor

    A bit slow. Was it reving out?

    Jeff

  3. #3
    Join Date
    May 2020
    Location
    Stokesdale NC
    Posts
    314

    Default Re: How to check if speed is good on 20hp mariner outboard motor

    As in you need a tachometer to compare what your engine is doing flat out to what book spec says it should do.

  4. #4
    Join Date
    May 2007
    Posts
    9,267

    Default Re: How to check if speed is good on 20hp mariner outboard motor

    I have a 14 foot deep v aluminum (Princecraft Fisherman) with the console installed (used to be an option).

    With two of us in the boat, plus our junk, pushing it with a 15 horse Mariner (1991 model), on calm water I get a hair over 30 km/hr. Unless your boat is a very heavy fiberglass model, that may be waterlogged, you should be eaisily geting about 3 times the speed out of a 20...
    Graham

    A "professional" is someone who gets paid for their work - it doesn't necessarily mean they are good at it :)

  5. #5

    Default Re: How to check if speed is good on 20hp mariner outboard motor

    What he said��

  6. #6
    Join Date
    Sep 2019
    Location
    toronto
    Posts
    14

    Default Re: How to check if speed is good on 20hp mariner outboard motor

    Quote Originally Posted by galamb View Post
    I have a 14 foot deep v aluminum (Princecraft Fisherman) with the console installed (used to be an option).

    With two of us in the boat, plus our junk, pushing it with a 15 horse Mariner (1991 model), on calm water I get a hair over 30 km/hr. Unless your boat is a very heavy fiberglass model, that may be waterlogged, you should be eaisily geting about 3 times the speed out of a 20...
    So what should i check. Mine is 14.5 aluminum sylvan boat. Please advice
    Last edited by Theshoaibahmed; 08-10-2020 at 06:59 PM.

  7. #7
    Join Date
    May 2020
    Location
    Stokesdale NC
    Posts
    314

    Default Re: How to check if speed is good on 20hp mariner outboard motor

    The first thing to check is are the throttle plates wide open when they should be. Second since you changed the trigger I would see if the timing is correct.

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