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  1. #1
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    Vent plugs tempest plus on 520 dvx

    What vent plugs,if any at all are u running. I have a 2000 520 dvx with mercury 225 optimax with 25p tempest plus. Looks like small plugs in right now. Last night first full tournament load with both tanks full livewells full and me 220 and fishing buddy 270 with about 100 pounds of extra tackle and beverages. Pretty slow out of the hole i would say a good 6 to 7 seconds to get on plane. Also chasing a rough idle in engine so just trying to get a feel what this boat should do as it is a new boat to me.
    1992 190 SC with 2001 Mercury 200 EFI

  2. Ranger Boats Moderator jc2bg's Avatar
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    #2
    What RPMs were you running when the nose of the boat started to drop? If less than 3500 RPMs, you either need more venting or less pitch in the prop. (Or possibly the engine is too deep.) It’s not uncommon, with water heating up and a heavy load, for an outboard to be slower spooling up and getting into the optimum horsepower range. Try pulling 1 of the plugs entirely, which is easier than changing from small holes to bigger holes, and see what that does to your RPMs at breakover. Optimum is 3500-3900 RPMs at breakover. For the rough idle, it’s probably best to post on the Mercury forum.
    John Clark — Findlay, Ohio

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    #3
    I would try 1 solid and 2 wide open if it was me
    Last edited by jt c; 06-18-2018 at 12:38 AM.

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    #4
    Hello,
    I have a 521DVX with Mercury 250 with a tempest plus also.During the summer I run with only one large plug in no others. Winter I run two large plugs.

  5. Member
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    #5
    Quote Originally Posted by jc2bg View Post
    What RPMs were you running when the nose of the boat started to drop? If less than 3500 RPMs, you either need more venting or less pitch in the prop. (Or possibly the engine is too deep.) It’s not uncommon, with water heating up and a heavy load, for an outboard to be slower spooling up and getting into the optimum horsepower range. Try pulling 1 of the plugs entirely, which is easier than changing from small holes to bigger holes, and see what that does to your RPMs at breakover. Optimum is 3500-3900 RPMs at breakover. For the rough idle, it’s probably best to post on the Mercury forum.
    Thank you for the reply. Yes it is about 3000 at breakover. No jack plate and RPMs are right at WOT. Just trying to figure out what is new boat and what is engine. Did post about engine in merc forum they have been great.
    1992 190 SC with 2001 Mercury 200 EFI

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    #6
    [QUOTE=jt c;9438389]I would try 1 solid and 2 wife open if it was me[/QUOTE

    Thank you
    1992 190 SC with 2001 Mercury 200 EFI

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    #7
    Quote Originally Posted by 521rangerman View Post
    Hello,
    I have a 521DVX with Mercury 250 with a tempest plus also.During the summer I run with only one large plug in no others. Winter I run two large plugs.
    Thank you
    1992 190 SC with 2001 Mercury 200 EFI

  8. Member
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    #8
    Ok up date. Pulled one plug and had both my boys (15 year old 250 and 13 year old 120 pounds) full live wells and much better hole shot. Ran at night speed just to make sure prop would grab and no problems. Just need to figure out rough idle and we are good to go.
    1992 190 SC with 2001 Mercury 200 EFI

  9. Ranger Boats Moderator jc2bg's Avatar
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    #9
    If you had a much better hole shot with 370 passenger pounds on board, I wouldn’t mess with it any more at this time. Hopefully you won’t always be so heavily loaded, and you don’t want to over-ventilate if you happen to be going solo.
    John Clark — Findlay, Ohio

  10. Fishfarm (Jay) fishfarm's Avatar
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    #10
    I carried pretty much the same load when i had a 225 on mine with a 25 tempest and used 1 large plug
    2000 520vx Ranger
    250 PRO XS
    SERIAL#2B115788/ 25P Fury 4/ 25P Fury 3 blade