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why does 1977 CC Commander 410 need excessive priming

Discussion in 'Chris Craft Constellations & Catalinas' started by usrjsw, Jul 28, 2009.

  1. usrjsw

    usrjsw New Member

    Joined:
    Jul 27, 2009
    Messages:
    1
    Location:
    Shakopee and Lake city Minn
    my 1977 410 w/twin 454's needs to be primed (pumped ) 15 times or more when engines ( both ) are cold. They start immediately 8 to 10 hrs after having been run. Experienced marine techs have not found any obvious reason; new rotors distr caps and carbs were kited last fall. No one knows what would allow gas to run back after sitting idle for day or more. Suggestions please. Am planning to instal electric marine fuel pumps no matter.
  2. K1W1

    K1W1 Senior Member

    Joined:
    Sep 30, 2005
    Messages:
    6,400
    Location:
    My Office
    Hi,

    Is it possible your tanks are not well vented and a vacuum is forming which sucks the juice out?

    You could also fit an inline check valve near the motor.
  3. NYCAP123

    NYCAP123 Senior Member

    Joined:
    Mar 14, 2008
    Messages:
    7,977
    Location:
    Long Island, NY
    I've always found that once you start pumping an engine it seems to require it more and more from then on. I was also taught way back when that instead of pumping the throttle you should advance it about half way, bring it back to idle and advance it again slowly as you engage the starter. Not being a mechanic I DK the reasoning. Old wive's tale or good advice?

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