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IDLE RPM ADJUSTMENT

fandangofandango Posts: 69 Deckhand
I have a 1991 evinrude 150 hp-v6- 60 degree outboard.

PROBLEM: I have re-built all 6 carburators and now the idle RPM using a water hose is 1150 to 1200. I have been told that the RPM needs to be within 600 to 700.

How do you adjust the idle RPM.

please advise.

STAY SAFE.

Replies

  • BillgranBillgran Posts: 349 Deckhand
    If the motor idle speed was OK before cleaning the carbs, then chances are the linkage adjustment is not correct. All the throttle plates have to be completely closed and all 6 open at the same time. Make sure the spark advance plate returns smoothly to its stop at idle, the original spring was known to break. The replacement design works well.

    Idle speed can only be adjusted with the engine in the water at the proper level. On a flusher there is no backpressure on the exhaust and the motor will run faster because it is now leaner than it should be.

    To adjust the idle, there is a Pozi-Drive screw on the advance arm - looks like a Phillips screw. Loosen it a couple turns and ONLY move the inner ratchet lever one click at a time to advance the timing which increases idle rpm. Do not touch or move the outer ratchet as that is for WOT timing. The correct idle is 650-750 rpm using an accurate tach. Your boat tach is not accurate at that low rpm, unless it is a digital.

    This link shows the advance arm and screw at the top of the image.

    http://im1.shutterfly.com/procserv/47b5d626b3127ccecb9af15a2a7400000016108CcOHLls2bA9vPhQ


    Here is a link for an inexpensive digital shop tach

    http://community.evinrude.com/t5/Performance/Technical-Tidbits-With-Bill-Grannis-Handheld-Digital-Tachometer/ba-p/3482
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    "There is never just one thing wrong with a boat"
    --- Travis McGee


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