1969 Mercury 35 H.p. Missing At Idle

Discussion in 'Bubba's Outboards' started by glenmorebuckman, Dec 31, 2006.

  1. glenmorebuckman

    glenmorebuckman Member

    Caneyville, Ken
    My mercury has a miss at idle when it's first started. After running it for about 2-3 minutes at WOT across the lake it runs fine until you let it set and cool off again. I mean it has to set at least 3-4 hours before it will start missing again at idle. Once it's warmed up it runs like a brand new one. It did this two years ago and I replaced the points and it was fine until last spring when it started again. I've checked the points and there still adjusted right . I don't think it's the carb. it just sounds like it's in the fire. Do coils cause these symptoms? Could there be moisture getting in one of the coils?
  2. Bubbakat

    Bubbakat New Member

    Sounds like a plug wire or plug breaking down. The next time you get a chance after dark hook it up to the muffs and take the bonnet off and look at those plug wires to see if any of them are jumping fire any where.

    I would also do a compression ck and then do a decarb. You might run some seafoam thru it mixed with the fuel and that might clean out the low idle jets if there are any thing in there. If the carbs haven't been rebuilt in a while then the needle and seats could be worn out but that shouldn't clear up after warm up though.
    If the plugs haven't been changed in awhile it might be time for a set.
    I don't use nothing but NGK in my mercs.

  3. trnsmsn

    trnsmsn New Member

    Missouri Originally Now I

    That's all I use in my Suzuki also.

    Have a safe & Happy New Years:smile2: