Yamaha f20 high RPM @ start?

Discussion in 'Outboard Maintenance' started by forever_right, Apr 6, 2009.

  1. forever_right

    forever_right Well-Known Member

    I have begun noticing my electric start f20 Yamaha starting and immediately revving over normal idle speed. Sometimes it takes a minute other times up to ten before it slows down. I'm uncomfortable shifting in and out of gear with the engine cycles still in high. Is this likely a warm up feature, or maybe the beginning of a computer problem. I'm just about to move it over to my new skiff and if it looks like I need to get a tech involved, I'd rather do it now instead of look at a new boat in the garage with no working engine.
  2. Brett

    Brett > PRO STAFF <

    I know on most new motors the start rpm is temperature controlled.
    Once the engine reaches operating temperature the rpm's drop.
    That's the reason the shop manual procedure for setting idle rpm
    reads "after engine has reached normal operating temperature..."
    So if the engine is very cold it will take longer for it to warm up.
    And the rpm's remain higher for a longer amount of time.

    Here's a link to an online parts diagram page:


  3. forever_right

    forever_right Well-Known Member

    Thanks, I had a suspicion that was the cause, but I makes me feel better to hear it from someone else.
  4. Brett

    Brett > PRO STAFF <

    Yeah, my last yamaha 50 did the same thing.
    I got in the habit of starting the motor,
    then putting things away, checking tackle and
    grabbing a snack or drink before going anywhere.
    When the rpms kicked down, that was when I'd bump into gear.
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