Slow idle and surging 350 MAG

YYZRCYYZRC Member Posts: 5,406 ✭✭✭✭✭
in Engine Discussions
On cold start, my port engine idles very slowly and surges between 400-600 RPM. Once it warms up it idles fine. Thoughts?
2006 390 EC
2008 350 EC
Georgian Bay
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Comments

  • aero3113aero3113 Member Posts: 9,763 ✭✭✭✭✭
    Swap IAC’s and see if the issue follows to starboard.
    2008 330EC
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  • Dream_InnDream_Inn Member, Moderator Posts: 7,919 mod
    I agree with aero, easy thing to check first.

    Dream 'Inn III -- 2008 400 Express

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  • rasburyrasbury Member Posts: 8,926 ✭✭✭✭✭
    edited June 2020
    Plugs and wires done last when? Old fuel in the tanks?
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  • YYZRCYYZRC Member Posts: 5,406 ✭✭✭✭✭
    I like that plan. Will try and report back. 
    2006 390 EC
    2008 350 EC
    Georgian Bay
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  • YYZRCYYZRC Member Posts: 5,406 ✭✭✭✭✭
    Fuel is new. Plugs, wires, cap and rotor are big question marks. Was hoping to tackle them over the winter as I dumped my fun money into the transom assemblies and bow thruster this year. 
    2006 390 EC
    2008 350 EC
    Georgian Bay
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  • rasburyrasbury Member Posts: 8,926 ✭✭✭✭✭
    It's not big money..at least comparing to that! These motors are pretty simple...
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  • Aqua_AuraAqua_Aura Member Posts: 2,702 ✭✭✭✭✭
    edited October 2020
    I just watched this video of a boater I subscribed to and he was explaining this exact issue and how he fixed it. He does have Volvo 8.1 though. Did you ever fix the issue? 

    There may have been another post on here I am thinking of but this is the first one that sounded familiar when I searched. 
    1997 Bayliner 3988
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  • YYZRCYYZRC Member Posts: 5,406 ✭✭✭✭✭
    Yep. New IAC fixed it. I tried the Windstar one and it did not work. Went OEM. 
    2006 390 EC
    2008 350 EC
    Georgian Bay
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