Results 1 to 10 of 10
  1. #1
    New Member
    Join Date
    Aug 2000
    Posts
    23
    Location
    hutto,tx 78634

    Default jd 850 3cyl

    my neibor has a 85 jd 850 with the yanmar 3 cyl. it just started seeping oil at the head gasket, getting harder to start, and wont idle. has 682 hrs and been maintained by dealer. what should he do? is this a problem? how hard is this motor to overhaul? did not overheat and has not been run low on oil but his wife does mow with this. any help is appreciated!!!

  2. #2
    Super Star Member RoyJackson's Avatar
    Join Date
    Nov 2001
    Posts
    18,663
    Location
    Bethel, Vermont
    Tractor
    John Deere 4400 MFWD, Deere 855D UTV, Z920A Zero Turn Mower and assorted implements

    Default Re: jd 850 3cyl

    If it's leaking at the head gasket, it's not holding compression (hence, the hard starting and inability to idle).
    As to why the gasket blew..well, you said it hasn't overheated. Are you sure?

    Nevertheless, I'd pull the head off and take it to the dealer or a machine shop. The machine shop can tell you if the head is warped. If not, put a new gasket on it and torque it properly!!!. You'll have to re-torque after so many hours (you really need the shop manual for this). If you don't know what proper torque technique is, let the dealer do the job.

    If the head is warped, you may have to strip the head down to a bare casting (leave the valve seats in though). The machine shop can mill it flat for you. You want the minimum amount of material taken off..or whatever the shop manual requires. There may be thicker gaskets available to account for the material removed from the head (if it comes to that). This is to maintain the correct compression ratio.

    By the way, when you pull the head off, look for cracks around the head and block. If you seeing oil, the crack may have started at one of the oil passages. Cracked heads can be welded, but if it is cracked (and I hope it isn't!!!), you might want to start looking around for replacement parts. If the block is cracked (unlikely as it is)...that's beyond my realm of expertise.

  3. #3
    New Member
    Join Date
    Aug 2000
    Posts
    23
    Location
    hutto,tx 78634

    Default Re: jd 850 3cyl

    thanks,roy. ill tell him, the coolant overflow and radiator are full so i dont think it overheated , BUT when she was driving anything could have happened, the dash just has idiot lights and she swore she never saw anything. this just happened recently and she said it just started running bad after mowing for a time. could this have happened over a period of time?

  4. #4
    Elite Member
    Join Date
    Feb 2002
    Posts
    3,857
    Location
    western,pa.
    Tractor
    Kioti DK 35

    Default Re: jd 850 3cyl

    msg,
    I put a tempature guage on my 850 for under $30.
    When field mowing my screen and radiator would plug quite often and the temp light would come on. But by then you are already overheated.
    Parts stores or Wal-Mart have temp guage kits(cheap).
    I used a hole saw and drilled the right side of the dash panel (near the light switch) for the guage.
    Roy is right ,it sounds like the head gasket.
    You could have a compression check done before tear down to get a better idea !

  5. #5
    Veteran Member
    Join Date
    Jul 2002
    Posts
    1,598
    Location
    Greene Co, Arkansas
    Tractor
    JD 1050 2wd, Case 580D 2wd

    Default Re: jd 850 3cyl

    Check for grass buildup on the grills and on the radiator screen... It really sounds like it overheated. My 1050 got hot enough to trip the light once from dead grass fluff on the radiator screen. I shut it down, cleaned it off and went to lunch to let it cool a bit.

  6. #6
    New Member
    Join Date
    Aug 2000
    Posts
    23
    Location
    hutto,tx 78634

    Default Re: jd 850 3cyl

    we already know compression is down cause its hard to start, looks like we'll have to yank the head. thanks!

  7. #7
    Veteran Member DUMBDOG's Avatar
    Join Date
    Jul 2002
    Posts
    1,068
    Location
    Central ND, Central FL
    Tractor
    NH 1630 W-7308 FEL/ Kubota L4630GSTC W-LA853 FEL WQ/A-CC 2544

    Default Re: jd 850 3cyl

    When I mow, I have to stop and clean the grill off every half hour or so because of the cottonwood trees, they have all kinds of fluff in the air that clogs of the front of the tractor, I just watch the heat gauge and when it goes up to the top of the heat range, it is time to stop and clean the grill, the heat gauge goes down right of way then.

  8. #8
    Veteran Member
    Join Date
    Jul 2002
    Posts
    1,598
    Location
    Greene Co, Arkansas
    Tractor
    JD 1050 2wd, Case 580D 2wd

    Default Re: jd 850 3cyl

    Unfortunately, The 1050 only has a light. About 1-2hrs. (every water break I guess) I stop, clean the outer grills off, and take a peek at the radiator screen. Not a big hassle. I've found a long bristle, old car washing brush to be a great gadget for cleaning the grills.

  9. #9
    Silver Member
    Join Date
    Jul 2000
    Posts
    223
    Location
    Western,MA
    Tractor
    JD 850, L130, 317

    Default Re: jd 850 3cyl

    reading the thread and had a Quick question what do you use for the sending unit on the 850 are they metric?

  10. #10
    Veteran Member
    Join Date
    Jan 2002
    Posts
    1,927
    Location
    Home-1+ acres New Hope, TX / 24 acres-Fannin County
    Tractor
    JD 950

    Default Re: jd 850 3cyl

    The 850 is Japanese made. I think you will find everything on it is metric. At least everything I have found on my 950 is.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
© 2014 TractorByNet.com. TractorByNet is a registered trademark of IMC Digital Universe, Inc. Other trademarks on this page are the property of their respective owners.