25 Hp Merc - How does primer knob work?

Discussion in 'Boats, Blinds, & Gadgets Forum' started by Wingmead, Nov 19, 2007.

  1. Wingmead

    Wingmead Elite Refuge Member

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    I recently bought a 2003 25hp Mercury. Looks and runs showroom new... but what do you do with the "pull to prime" knob on the left? I couldn't find a manual on the www so I thought that I would ask here. Right now, I'm leaving it alone, but latter in the year as the temps drop I want to know how to adjust it to maintain quick starts and smooth idle. Thanks :tu
     
  2. meeshforty

    meeshforty Refuge Member

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    My 25 Merc is actually an 05. If they are the same, my says "pull to choke". If it hasn't been run or is cold, i pull that out and start it. Depending on temps, will run for a few seconds to a minute or so. If it is cold usually dies. Then I push it in, start as normally do and its ready to run. Hope this helps. Let me know if I need to explain better.
     
  3. Freeroamer

    Freeroamer Senior Refuge Member

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    I have a 25 2002 Merc. They are sure cold blooded. I had problems with the fuel line not snapped in all the way at the motor side causing it to die when throttling up in either gear. Also make sure the primer bulb is hard. Just pull the choke out, pull the cord till it either starts or attempts to start then push it back in.

    Also make sure your spark plugs are in perfect shape. They can sure be the problem for cold starting.
     
  4. JDHog

    JDHog Senior Refuge Member

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    Got a 2005 and yes get the bulb hard and pull the knob out , give it a pull or if you lucky hit the electric start. It wiil run cold push it in after about 20 sec and your on your way .
    good luck it works for me .
    jdhog
     
  5. billy

    billy Senior Refuge Member

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    The pirmer knob does just what it says. When you pull it out it presses down on a plunger on the side of the carb and gives a little shot of fuel into the carb. By turning the nob you can advance the timing to help it start. The choke is electronically controlled. When it's real cold 2-3 pulls on the knob will help it to start more readily, but too many will flood it. Of course it might be difficult to start and idle to warm up, all Merc's hate to go slow.
     
  6. Wingmead

    Wingmead Elite Refuge Member

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    Thanks all...

    What is supposed to happen when you rotate the knob?

    There are about 10-12 indent positions that move a couple of levers and a steel linkage, but for the life of me when I turn it neither the rpm nor idle quality changes. I just put everything in the middle position.




    (thanks billy... we posted at the same time and yours came up first)
     
  7. billy

    billy Senior Refuge Member

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    My 20 is the same way. I can't tell the difference in turning the knob and don't worry too much about it.
     
  8. BadBowtie

    BadBowtie Elite Refuge Member

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    You can adjust inside on the rotary knob inside and see what it is doing. But mine does not seem to make a diff either.
     
  9. RETRO

    RETRO Elite Refuge Member

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    By turning the knob it is like a fast idle..
     
  10. scoobyduck

    scoobyduck Senior Refuge Member

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    X2 on what Retro sayd! It's also handy when in a going against the grain on a river and checking trot lines, you won't have to keep accelerating it back and forth.
     

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