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Wrong Oil = power loss?

Discussion in 'Lawn Mowing' started by HOMER, Apr 4, 2005.

  1. HOMER

    HOMER LawnSite Gold Member
    Posts: 3,183

    25 Kohler with a lot of hours has lost a lot of power. I think the last time I changed the oil I used 10-40 vs. 10-30.............might have used straight 40w. I cannot come up with an explanation for the loss of power other than it might need a rebuild/repower. The mechanics that have looked at it can't either. I was wondering if the wrong oil could cause problems with the lifters which in turn would create a loss of power.

    Coils are fine.....compression is in limits, rpm's are at 3850, plugs are good. This has puzzled me and I don't think it's time to spend tha big dollars yet.......but I can't figure out why the sudden loss of power. I cut my yard yesterday with it and once it got hot it seemed to run somewhat better but still not 100% of what it could run. Can oil do this???? :help:
  2. Richard Martin

    Richard Martin LawnSite Fanatic
    Posts: 14,700

    If there were something wrong with the lifters you would certainly know it. I'm going to assume that you've already done all of the basic stuff (air cleaner, clean fuel, etc..) and recommend that your mechanics do a leak down compression test. I have a feeling that you've blown a head gasket by running the engine at 3800+ RPM. I've seen a bunch of Kohlers blow head gaskets (including one of my own) and all of them have been reved way past 3600 RPM. Oh yeah, I've never heard of oil causing a performance loss.
  3. Charles

    Charles Moderator Staff Member
    Posts: 7,879

    I had a Kohler 20 hp that went blewy at 2500 hours. Funny how it died after I started using synthetic oil to try and get it to last longer. The first sign of it going bad was oil shooting out of the carb. Never did notice a loss of power
  4. rodfather

    rodfather LawnSite Fanatic
    Posts: 9,501

    Kohlers were known for years to have head gasket problems...but I thought they solved that in the last couple of years?

    JOEWOOD LawnSite Member
    Posts: 146

    Hello Homer,

    Got the same problem with my Gravely Pro-Master 200.

    Also when machine heats up there's a slight increase in power. The crazy thing is, just got it back from Cam Replacement and the Mechanics gave it the Heads-Up!

    2000 Tundra V8 Extended Cab :cool2:
    Gravely Pro-Master 200
    John Deere 737
    And all the trimmings
  6. Norm Al

    Norm Al LawnSite Bronze Member
    Posts: 1,227

    lawn mowers dont use hydraulic lifters so the oil wouldnt affect it like your common car!
  7. Jpocket

    Jpocket LawnSite Silver Member
    Posts: 2,278

    Yes they do a 25 kohler has juice lifters
  8. Richard Martin

    Richard Martin LawnSite Fanatic
    Posts: 14,700

    Kohlers do. It looks very much like a Chevy lifter.
  9. mowtime

    mowtime LawnSite Member
    Posts: 79

    have you checked your exhaust system to see if it is clogged or if it has a spark arrestor that is clogged.
  10. barnard

    barnard LawnSite Senior Member
    Posts: 618

    If you've got spark and compression the problem is fuel delivery. Likely partially clogged jet.

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