1958 envinrude 35 HP big twin running rough

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This topic contains 23 replies, has 9 voices, and was last updated by  fleetwin 3 days, 16 hours ago.

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  • rvdriver

    Replies: 29
    Topics: 6
    #154121

    My 1958 Evinrude 35 HP big twin has been running rough. It has a new coil, new plug wires, cleaned fuel filter, new carb kit with jets and float and fresh unleaded fuel with correct oil mixture and marine Sta-Bil additive. It was running great after recent new carb kit installed.

    It is running rough on idle and it will not go to full throttle without sputtering and eventually quitting running. .

    I’ve included pictures of the two plugs.

    Tell me what you think my issue might be. Thanks for the great help this site provides.

    Picture of the boat we built as well. She’s too beautiful not to grace the lake!

    Attachments:

    lindy46
    US Member - 1 Year
    Replies: 231
    Topics: 16
    #154278

    Did you replace only one coil? What about the points and condensers?


    rvdriver

    Replies: 29
    Topics: 6
    #154311

    Yes both coils, plugs, plug wires, points and condenser all replaced and new.

    Thanks!

    Steven


    outbdnut2
    US Member - 1 Year
    Replies: 1030
    Topics: 51
    #154345

    Have you checked compression?
    Dave

    RICHARD A. WHITE
    RICHARD A. WHITE
    US Member - 1 Year
    Replies: 1447
    Topics: 110
    #154363

    Did you rest the timing and did you use the proper ignition timing tool or did you use feelers gauges?

    Richard

    Better than OEM Timing tools

    http://www.richardsoutboardtools.com

    or email:

    classicomctools@gmail.com


    outbdnut2
    US Member - 1 Year
    Replies: 1030
    Topics: 51
    #154431

    After reading your post again, since you had it running great at first, I’d first check your points adjustment again and if that doesn’t fix it, go back into the carb and look for any small fleck of dirt, and spray carb cleaner through all passages again with needle valves removed. With new gas lines, I’d be suspicious of small rubber fragments shaved loose when pushing gas lines onto mating nipples. This can happen downstream of the filter. That bit me twice this summer.
    Dave

    fisherman6
    fisherman6
    US Member - 1 Year
    Replies: 1586
    Topics: 35
    #154434

    If you are using ethanol-blended unleaded your carburetor may be worth a look. You state that you put a new kit in your carburetor. Did that kit include a float? I know even the new OEM kits still have a cork float in them. They are a lighter color and are supposed to be coated with an ethanol resistant coating but I have not tested this. I only run ethanol-free gasoline in my outboards. If you did not replace the float and it still has the shellac coating, the ethanol will dissolve the coating and it will end up in the bottom of your carburetor’s float bowl in little gummy bits and block fuel flow. It takes a little time for this to happen, but if the carburetor is not run dry each time and the float is floating in fuel all the time, it will happen. Marine Sta-Bil has the ethanol additive in it too, but I’m not convinced that will save a shellac coated cork float from the effects of the ethanol. I’m not sure what the Sta-Bil does chemically, but it does not magically make the alcohol disappear.
    -Ben

    OldJohnnyRude on YouTube


    frankr
    US Member - 1 Year
    Replies: 3790
    Topics: 42
    #154464

    Until proven otherwise, I suspect it is ingesting water into a cylinder.


    chris-p
    Canada Member - 1 Year
    Replies: 2425
    Topics: 154
    #154514

    I was thinking along the same lines as Frank.

    However, first, start with the basics.

    What is the compression, cold and dry?

    Does the spark jump a 1/4″ gap on an adjustable inline spark tester?

    Most Big Twins of your Vintage should fall in the 90 to 110 psi range. If so, and you have a bright blue spark that jumps a 1/4″ gap, I would look at your exhaust gasket, head gasket, etc… for water intrusion.


    jerry-ahrens
    US Member - 1 Year
    Replies: 1005
    Topics: 70
    #154575

    Did you use a Sierra carb kit along with Sierra points? Both are terrible, and could cause your symptoms. i made the mistake of trying Sierra points a few yrs. ago, mainly because I can by them dirt cheap. I found them to be of terrible quality, and went right back to OEM. Same goes for the carb kit, that does not come with a new float from Sierra.
    Is your motor running a single line hose with a fuel pump? If so, and if you are using an aftermarket fuel line and bulb from Wal mart, or whatever, that will eventually be an issue. The inner barrier liner in those aftermarket fuel line will eventually come loose and clog the line shut. I’ve had to replace a truck load of those things. The motor will start and run for a short distance, then slow down and eventually stall out. Just a few things you may want to consider. Hope this may be of help.


    fleetwin
    US Member - 1 Year
    Replies: 2426
    Topics: 27
    #154582

    Until proven otherwise, I suspect it is ingesting water into a cylinder.

    Hey Frank, just wondering what I am missing here. You seem convinced this is a water ingestion issue, what is pointing you in this direction? I see the plugs look real rich, but I don’t see water droplets, etc. D


    frankr
    US Member - 1 Year
    Replies: 3790
    Topics: 42
    #154588

    Actually, not “convinced”. More like “suspect maybe.” One of the plugs looks cleaner, like maybe washed/steamed down. Just something to think about, since it seems the usual stuff has already been addressed.


    rvdriver

    Replies: 29
    Topics: 6
    #154604

    Frankr:

    Thanks for your comment. So what do you think about the carbon seal as a possible culprit?

    Steven


    rvdriver

    Replies: 29
    Topics: 6
    #154620

    Another question: I am running Champion J6C plugs. Should I run something else or maybe even a hotter plug?

    Thanks!


    rvdriver

    Replies: 29
    Topics: 6
    #154651

    I ran a compression check today and both cylinders were right at 120 psi. That was a welcome relief.

    Steven

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