Results 1 to 5 of 5
  1. #1
    Join Date
    Sep 2006
    west st.paul, mn, usa

    Default "My 63 Johnson 10 H.P. (mo

    "My 63 Johnson 10 H.P. (model QD24) is running excellent but is dripping unburnt fuel/oil mixture I believe out of a pin hole (vent) onto prop thus accumulating onto floor. I was concerned about it and have been since told that the lower crank shaft seal probably is the culprit. Due to cost of repair I have ordered Seloc manual and may plan to do this job myself. The motor has had lower unit serviced (seals & impeller) and tune up in August. Do you think lower crank shaft seal is causing this accumulation? If so, will Seloc manual step by step this fix? Please help, Thanks..."

  2. #2
    Join Date
    Jun 2006

    Default I just went through this with

    I just went through this with a QD-23. I was told that it is caused by the condensation of unburned fuel in the exhaust housing. I had just rebuilt the motor and was only able to run it in a feed tank so it wasnt fine tuned. It was also suggested that part of the problem may have been the fact that I had it running in very cold water. After this was explained to me I stopped being concerned. I may be wrong about this but I think if your "lower crankshaft seal" were bad that you would have a vacuum leak and the motor wouldnt run at all. I am assuming that this is the seal on the powerhead that allows access to the crank shaft? tom

  3. #3
    Join Date
    Feb 2001
    Central West Florida

    Default "As Tom states, that has nothi

    "As Tom states, that has nothing to do with the lower crankshaft seal. His explanation about the unburnt fuel is right on."
    We occasionally have questions. If you fail to answer, it may affect ours.

  4. #4

    Default "I believe this is a normal co

    "I believe this is a normal condition and does not requre repair. This is what I was told about this conditon on my 75 9.9Hp Evinrude:

    Black or Gray Oil Coming Out of Upper Exhaust Vent &/or Lower Unit Holes : Many of these motors are basically used as a secondary motor, & usually then as a trolling motor, and are ran for considerable length of time at a lower RPM. The fuel oil mixture ratio of 50-1 is probably too rich by some. The black oil that seeps out of the motor is just unburned oil from the gas mixture. The black color is coming from the carbon created during the pistons firing situation & is accumulated unburned inside the exhaust housing. The excess oil in the fuel is mixing & softening up the carbon, creating the black oozing oil. This oil seepage may not be evident until a day or week after usage, & then will seep out up to a couple of weeks later. It seems best for most boaters to then simply live with the idea that you may have to wipe it down after each usage."

  5. #5
    Join Date
    Jul 2006
    Montreal , Quebec, Canada

    Default "AND - make sure that the crud

    "AND - make sure that the crud that accumulates in those weep holes does not plug the lower exhaust cavity. If you store your motor in sub-32, then any trapped water will expand and crack something."

Similar Threads

  1. Suzuki DT15C Lower Crank seal
    By zingere in forum Suzuki Outboard Forum
    Replies: 2
    Last Post: 09-23-2010, 12:23 PM
  2. Stringer Tilt Housing Shaft Seal Replacement
    By gcban in forum OMC Sterndrive and Inboard Forum
    Replies: 11
    Last Post: 06-30-2009, 11:58 PM
  3. Rear crank oil seal replacement
    By ants in forum Mercruiser Sterndrive Archive
    Replies: 4
    Last Post: 06-25-2008, 02:14 PM
  4. Lower seal replacement
    By Mr. Underhill in forum Johnson Evinrude Outboard Archive
    Replies: 1
    Last Post: 07-13-2007, 08:16 AM
  5. Alpha 1 Prop Shaft Oil Seal Replacement
    By guyjg in forum Mercruiser Sterndrive Archive
    Replies: 8
    Last Post: 05-23-2007, 06:47 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts