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Hustler z losing power

Discussion in 'Mechanic and Repair' started by Billsz28, Sep 26, 2012.

  1. Billsz28

    Billsz28 LawnSite Member
    Posts: 70

    2007 hustler super z 60" with a 27hp kohler command vertical crankshaft engine. Was having issues with it running rough and losing power under load. Cleaned the carb and all was well for a while, symptoms started again and I decided to replace the carb because of the terrible shape it's in. I do not have the machine in front of me so no model/serial numbers at the moment.

    My next step was to change the spark plugs, they are not in good shape.

    The mower is maintained at regular intervals. Any suggestions on what to check/look for next? Any help would be greatly appreciated.

    Thanks-bill
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  2. lkendall

    lkendall LawnSite Member
    Posts: 157

    i have the same mower with the same piece of junk engine.. its in the shop right now with the same symptoms, mine was the blown head gasket again..
     
  3. Billsz28

    Billsz28 LawnSite Member
    Posts: 70

    Thanks for the reply. Did you have any loss of compression, blue/grey smoke, or wet oil spots around the heads?
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  4. Billsz28

    Billsz28 LawnSite Member
    Posts: 70

    I don't know if this helps but model: 928988A
    Serial: 07120297.

    Could this problem be caused by bad coils? I have been following the Kawasaki thread, and although this engine is kohler it seems to have similar symptoms.

    Secondly what exactly does a black Gunky spark plug signify? Oil seeping past spent oil rings into combustion chamber, worn valve guides?
    If that ends up being the problem, how difficult is it to replace the guides? Does it involve removing the head and replacing the gaskets as well? Thanks
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    Last edited: Sep 27, 2012
  5. tlmarrio

    tlmarrio LawnSite Member
    Posts: 27

    Hey Bill,

    Look at my post on page 11 called Kohler cv 750 need help please. This problem had me pulling my hair out. Ended up being the coils and wire harnes that connets them. Read the entire post I think you might find it interesting and hopefully helpful. Good luck with your problem.
     
  6. tlmarrio

    tlmarrio LawnSite Member
    Posts: 27

    By the way Bill I also have a 2007 Hustler super z xr7 66in. deck with a 30hp kohler.
     
  7. Billsz28

    Billsz28 LawnSite Member
    Posts: 70

    Thanks tlmarrio I found the thread interesting. Unfortunately I think I found bad news. I got the mower up to my shop to check it out yesterday and found that the machine had burned about 1/3+ quart of oil since I saw it last Saturday, and it was not used heavily by any means this week. Also the machine is bone dry on the bottom so no leaks.

    The machine has 639 hours. I pulled both plugs again and replaced them with new. The #2 cylinder plug looked fine while the #1 cylinder was black and showing signs of oil getting into
    the combustion chamber.

    Also upon inspection the area around th head gasket on cylinder #1 was very dirty with what appeared to be oil? The #2 cyl. Was fine and clean. I have attached pics of both spark plugs and of the Area around #1 cyl. head gasket being dirty.

    [​IMG]

    [​IMG]


    I observed major blow-by Comming out the oil dipstick tube. Somehow the crankcase is becoming pressurized. My guess is spent rings on the #1 cylinder and/or worn valve guides. Any ideas?

    I am awaiting my leakdown tester and I will post results as soon as I can.

    How cost/labor intensive is reconditioning the cylinder bore/ piston&rings to fix the problem? Also depending on the leakdown results would the valves have to be reground and the faces recut?

    I am an auto mechanic, but service small equipment/ rebuild 2-cycle equipment on a daily basis so I think I could handle this with the right tools. Thanks in advance. I'll keep the thread updated in case others have similar issues
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  8. Dave

    Dave LawnSite Senior Member
    from RI
    Posts: 315


    Did you check the head gasket real well in where it seperates from the push rod valley. the briggs ohv are noted for leaking in that area it creates enough neg pressure in the block that oil blows out the fuel pump diaphram.
     
  9. Billsz28

    Billsz28 LawnSite Member
    Posts: 70

    I did thoroughly check the gasket and no actual wet spots aside from what is displayed in the photo

    Where is the crankcase breather reed located on a vertical crankshaft engine. I am familiar with the kohler command horizontal but upon first glance it looks different?
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  10. Dave

    Dave LawnSite Senior Member
    from RI
    Posts: 315

    I believe it is on the valve cover , did you check your air cleaner to see if it was wet with oil. If there are no ridges/ scores in this cylinder , I doubt it is rings, . its to bad you did not do a leak down as it ussaly tells you more than a compression test, does you dip stick have a oring in it??? and is there any noticble oil leaks around the 2 seals. I would still lean toward gasket as they were noted for them to have issues . recheck your block again for a thing staining line going acrosss to the oil champer side
     

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