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Yanmar 2GM20F Fuel Injection Pump Leaks!

Discussion in 'Ask All Sailors' started by mz4wheeler, Sep 14, 2015. Add this thread to a FAQ

  1. mz4wheeler

    mz4wheeler

    Joined Mar 11, 2015
    354 posts, 25 likes
    Hunter 33.5
    US Tacoma, WA
    [Please see attachment photo]

    My 2GM20F fuel injection pump is seeping diesel when the engine runs. It is not that excessive, but enough to make things reek of fumes. This has been going on for quite a while and I temporarily fixed it by re-seating #12 a while ago. Well, it is back, worse than before.

    Without taking the whole thing to a shop for a rebuild (sailors are frugal), I was hoping that someone has experience taking these things apart enough to assure me that if I remove #12, parts won't spring all over my engine compartment [grin].

    According to the parts diagram:

    #13 is an o-ring (I'm hoping THIS is the issue)
    #10 is a gasket
    #6 is a gasket

    Questions:

    1) Can I safely remove #12 and replace the o-ring (#13)?
    2) Can I also replace #10 and/or #6, or are these integrated into the plunger

    My goal is to just stop the leaks. Other than this, the engine runs perfect.

    Thanks!
     

    Attached Files:



  2. kloudie1

    kloudie1

    Joined Nov 6, 2006
    7,847 posts, 521 likes
    Hunter 34
    US Mandeville Louisiana
    MZ, the o-ring (13) is the seal that is leaking unless there is a crack in the body of the pump or the big top nut (delivery valve spring holder). Make sure the leak is not between the top tapered fitting on the delivery tube. The O-ring, #13 can be replaced by removing the fuel line from the top, then slowly backing out the "spring holder" #12.. The spring should release before the threads come undone so there should not be a "sproing" (spring pops out and flies through the ceiling, never to be found again) The pressure the o-ring sees is full injection pressure, so once it starts leaking, it will be cut by the escaping high pressure fluid. That o-ring is a specific material and hardness, so I wouldn't use one except from Yanmar or a reputable diesel injector repair shop. That job must be surgically clean to not cause damage to the pump.. clean off everything in the area before beginning and have clean rags ready to cover to keep any dust or debris out.. Let us know how it turns out !
     


    woodster likes this.
  3. mz4wheeler

    mz4wheeler

    Joined Mar 11, 2015
    354 posts, 25 likes
    Hunter 33.5
    US Tacoma, WA
    Thanks a lot kloudie! I just wanted to make sure that if I remove #12, things won't either fall out (or worse, IN) the engine. BTW, the best way I have found to really clean an area of an engine is a can of brake cleaner. Evaporates in 30 secs. I'll be sure to report back in on how it went.
     


  4. Sailm8

    Sailm8

    Joined Feb 21, 2008
    1,487 posts, 162 likes
    Hunter 29.5
    US Punta Gorda
    I had the same leak and the O rings fixed it. If that gives you any piece of mind.
     


  5. mz4wheeler

    mz4wheeler

    Joined Mar 11, 2015
    354 posts, 25 likes
    Hunter 33.5
    US Tacoma, WA
    Yes, it does. :D Thanks!
     


  6. mz4wheeler

    mz4wheeler

    Joined Mar 11, 2015
    354 posts, 25 likes
    Hunter 33.5
    US Tacoma, WA
    Just a follow up on this job last September. It went smooth and no issues. I took a couple of photos, but none on the completed job. Hint: Brake cleaner, along with a wire brush did a fabulous job cleaning the area. It cleans and evaporates almost instantly. I replaced both o-rings and it hasn't leaked since. For the first time since I owned this boat, the engine doesn't leak anything. Someone once told me "all diesels leak"... Not true.
     


  7. woodster

    woodster

    Joined Sep 15, 2009
    6,240 posts, 262 likes
    S2 9.2a
    US Fairhope Al
    they only mark their spot
     


  8. Ken13559

    Ken13559

    Joined Oct 29, 2005
    1,878 posts, 62 likes
    Hunter 326
    SG Singapore
    All diesel leaks at some point in time. You just need to "find small, fix small" else it becomes a "found big, BIG fix". :)
     


  9. Jimmymak

    Jimmymak

    Joined Dec 2, 2013
    5 posts, 1 likes
    Hunter 336
    US Newcastle
    Hi guys
    I’m about to order the replacement o rings, however I wanted to ask- is it sensible to replace all 3 o rings at once ( I’ve got a 3GM), or just do one when a leak appears?
     


  10. kloudie1

    kloudie1

    Joined Nov 6, 2006
    7,847 posts, 521 likes
    Hunter 34
    US Mandeville Louisiana
    Might as well do all three.. Once you have it cleaned up, replacing the o-ring is not that big of a deal..
    Welcome to the forum, Jimmy.. good luck with the repair..
     


  11. Jimmymak

    Jimmymak

    Joined Dec 2, 2013
    5 posts, 1 likes
    Hunter 336
    US Newcastle
    Thanks mate much appreciated . I think I knew the answer to my question as I was typing it . I also have a hunter 34 (well 336) by the way. Great boat
     


    kloudie1 likes this.
  12. RoyS

    RoyS

    Joined Jun 3, 2012
    332 posts, 73 likes
    Hunter 33
    US Bay Pointe, Quincy
    This is from memory: The part numbered (12) must not be over torqued as it will distort the delivery valve. No.12 should be torqued to spec. (which I forget) and held from turning further when connecting the pipe to it. Keep in mind (10) is sold as a lapped unit and must be kept that way. Good luck.
     


  13. Charles Erwin

    Charles Erwin

    Joined Jan 30, 2012
    916 posts, 80 likes
    Nor'Sea 27 - "Kiwanda"
    US Portland/Anacortes
    29 - 32 ft lbs. Check for smooth movement of the rack whilst you tighten the delivery valve fitting. Important to do these one at a time so you cannot intermix parts - as already pointed out by RoyS. Check also the output tubes to verify the ends are polished and defect free. These can leak - the fuel seeps down to the holder threads and makes you think the pump is leaking when it is actually a corroded output tube end.

    Charles
     


    Last edited: Jul 12, 2018
  14. Jimmymak

    Jimmymak

    Joined Dec 2, 2013
    5 posts, 1 likes
    Hunter 336
    US Newcastle
    Thanks guys great advice! Will keep you posted on how I go
     


  15. MitchM

    MitchM

    Joined Jan 20, 2005
    625 posts, 79 likes
    Nauticat 321 pilothouse 32
    US Erie PA
    thanks to all who posted. the information above from these knowedgeable mechanics like Kloudie and roy and Charles is invaluable and is worth $$$$$$ to us shoestring budget people. my o ring is NOT leaking but i will sure keep this thread handy in my 'online boat maintenance' section for yanmars. ' Q: how many hours on the enigne when these o ring leaks start showing up ??
     


  16. Jimmymak

    Jimmymak

    Joined Dec 2, 2013
    5 posts, 1 likes
    Hunter 336
    US Newcastle
    Hi Mitch
    Yes my 3gm30f is nudging 2000 hours. Not sure if the previous owner/s had this issue before but it’s only on one tube... so far! I’m going to replace all 3 o rings to hopefully get me another 2000 hours
     


  17. Jimmymak

    Jimmymak

    Joined Dec 2, 2013
    5 posts, 1 likes
    Hunter 336
    US Newcastle
    Hi guys
    Just an update to say the o ring replacement went pretty well!! I replaced all 3 and the engine is back online . Only issue I found was trying to keep foreign matter out of the top of the injector pump once the delivery tube holders are out. If I had my time again I would use gaff tape or similar to cover the exposed holes. Thanks to everyone for your help and advice it’s much appreciated
     


  18. kloudie1

    kloudie1

    Joined Nov 6, 2006
    7,847 posts, 521 likes
    Hunter 34
    US Mandeville Louisiana
    Good to hear, Jimmy !
     



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