Volvo MD2B Longevity Tips

  • June 02, 2013 6:41 AM
    Reply # 1307399 on 1299876
    Deleted user

    I mix 1 ounce of two cycle outboard motor oil per gallon of diesel for running through "Old Thumper", my Volvo MD11C also original to Rhapsody. Runs smoother with less noise, smoke and vibration. I will try to post a video of the engine running later for comparison with yours. I think I'm around 2700 hours and also run muriatic acid mixed with fresh water through the engine using a raw water bypass system about once a year to clean out the cooling system.

    Last modified: June 02, 2013 6:43 AM | Deleted user
  • June 02, 2013 12:53 PM
    Reply # 1307572 on 1299876
    Deleted user

    Couldn't figure out how to post the video. The engine is in forward gear at the dock running at 950 RPM. 

    Last modified: June 02, 2013 12:55 PM | Deleted user
  • June 16, 2013 7:11 PM
    Reply # 1319751 on 1299876
    Deleted user
    So I am looking at replacing the engine mounts before anything else. I found NOS DF-100s for $15/per, they're in the mail. 

    I don't think any serious damage has happened yet from the engine being out of kilter, I'm most worried about the prop shaft. 

    This video shows the fwd end going into the tranny. Is the wiggle room on the key normal?

    I'm typing from my phone and its impossible to make the hyperlink work, I can't paste into the field. You'll have to cut and paste unless Jay can fix it. 



    Last modified: June 16, 2013 7:30 PM | Anonymous member (Administrator)
  • June 16, 2013 7:39 PM
    Reply # 1319771 on 1299876
    Anonymous member (Administrator)
    Stephen:  Fixed the hyper link - what you are seeing is NOT normal - and not a good thing as this should be a tight fit w/o any movement. 

    I suspect that the square headed nut has in the past gotten loose and overtime allowed just a little play to grow to the play your are seeing.  Or maybe it started with something in the prop etc. 

    IMHO - now either the shaft, key or the "tail" piece or all three have changed size.  While I have NOT had to fix this issue - I would recommend that all three of the above be checked and the issue resolved... 

    I'm hoping others will chime in here who have had this issue. 

  • June 17, 2013 6:06 AM
    Reply # 1320014 on 1299876
    Deleted user
          I can not tell anything definite from your video, but can tell you that it will need to be disassembled and inspected.  The video appears to show that the shaft keyway has been damaged.  I suspect that all three components (shaft keyway, key, and coupling) have been affected.  The pieces should be a "slip" fit w/no "wiggle" room.  You might consider the addition of a flex coupling after you have replaced the engine mounts and have the alignment in order.

  • June 17, 2013 9:56 AM
    Reply # 1320199 on 1299876
    Deleted user
    I've got WIFI now (at work) so I've uploaded a higher-rez version. The keyway is totally mangled.

    prop shaft key way
  • June 18, 2013 5:54 PM
    Reply # 1321439 on 1299876

    You need a new shaft coupling and key, and hope that the slot in the shaft itself is not too mangled.  If you can't find one up in Canada, contact me as one of my engine parts suppliers usually has them.  Buck Algonquin part # BUA50MVP400.
  • June 29, 2013 6:22 PM
    Reply # 1329911 on 1299876
    Deleted user
    So after this most recent oil change, I noticed the md2b overheating. Luckily I noticed right away (I think) as I was in the galley doing the dishes and saw steam coming out of the vented loop that vents to cockpit drain. 

    Working my way backwards from replacing the impeller, to cleaning the raw water strainer, next thing was to do a dive and see if the thru-hull was bunged up w/seaweed. Someone I bumped into reminded me to check the actual hose first, so I did that. 

    The hose clamps came off easy, but when I put pliers on the old hose to get a better grip the bronze screw on adapter (whatever it's called) snapped with almost no effort. Scary stuff. When I yank the boat to do the prop shaft I am definitely doing all the thru-hulls and seacocks. They all have that tell-tale pink tinge that means bad ju-ju is going on. 

    And the hose was jammed with junk. 

    Jay is going to post the pics for me. 

    Any general suggestions on the re&re of that hardware?


    Last modified: June 29, 2013 9:42 PM | Deleted user
  • June 29, 2013 6:58 PM
    Reply # 1329924 on 1299876
    Anonymous member (Administrator)

    Stephen: All posted - is that fitting bronze or brass -- the threads are pretty shiny...


  • June 29, 2013 7:31 PM
    Reply # 1329928 on 1299876
    Deleted user
    That's a good question. The 90° it went into was definitely bronze and had NO corrosion at all. 
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