What caused my 27 Kohler to fail?

Discussion in 'Mechanic and Repair' started by Shady Brook, Aug 4, 2006.

  1. Shady Brook

    Shady Brook LawnSite Bronze Member
    from Indiana
    Posts: 1,517

    I have a Super Z with 27 Kohler with 1000 hours that just died yesterday. Dealer said it had a broken rod, and was barely measureing oil on the stick, or it was stained dark on the tip of the stick. Feels it just burnt up.

    This mower had the oil changed about two weeks ago, or about 60 hours. The unit would loose burn very little oil between changes, and sometimes make oil via gas mixing with it. My workers are to check the oil daily, although they admitted they have not been doing so. I find it hard to believe that it used that much oil. It has never leaked oil, and there were no leaks before or after failure that we or the mechanic found.

    I think the engine has a low oils sentry, but am not sure if this will shut down the motor upon low oil pressure.

    I figured with low oil the engine would have seized but not have broken the rod. The engine was still running after failure which makes me think it was not siezed. Could low oil under these circumstances cause the rod to break? Could there be oil in the muffler?

    Any thoughts on what might have happened, or what questions to ask the dealer? I would appreciate it. I hate to fork our $2400 for a new engine.

    Thanks for your help.
  2. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,023

    You may have answered your own question with the above statement.
    A engine will not make oil when fuel enters the crankcase, The fuel thins the oil out and causes it to loose lubricating property's thus burning the engine up.

    You may check into a short-block engine, They are in the $ 820.00 range.
    I just finished assembling one yesterday. Should you go this route check the valves in the head that the rod broke in, The piston could have came up and slapped one bending it which was in my case. Also rebuild the carb. to prevent fuel contamination in the oil.

    Or you can check here for a replacement engine; http://www.smallenginewarehouse.com/

    Good Luck
  3. thecrankshaft

    thecrankshaft LawnSite Member
    Posts: 172

    Fuel can either enter the tank via a torn fuel pump diaphragm or leaking inlet needle and seat in the carburetor.

    The rod usually seizes to the crankshaft, but the momentum of the engine, blades spinning usually continues to turn the crankshaft and the rod breaks.

    If the rod failed from complete lack of lubrication, there will be no burnt oil on the metal transfer on the crankpin. If the engine failed from lack of lubrication, from fuel in the oil, there should be some burnt oil on the crankpin.

    The oil sentry turns on a light when oil pressure is low for mobile equipment, but for stationary equipment it can shut the engine down.
  4. tomo

    tomo LawnSite Senior Member
    Posts: 660

    Hello, was the engine using oil? I have found a number of destroyed engines due to oil con sumption[plugs fouled, burnt oil on top of pistons]Personal experience has shown oil consumption can grow rapidly and therefore draining oil to a low level therefore inviting engine damage. Picked up a Dingo engine the other day ,crank main journal futherest from oil pump had major wear . Cause was from oil consumption ,low level causing starvation to journal.[loads of burnt oil on piston] Kohler sumps are very small in capacity approx 1.5 quarts in service refill. approx 2 quarts new engine THERE IS NO ROOM FOR ERROR:hammerhead: 3 quart in service refill would be nice. tomo
  5. Shady Brook

    Shady Brook LawnSite Bronze Member
    from Indiana
    Posts: 1,517

    I still do not know anything more about the motor. The head of service was going to look at the engine a bit more yesterday, but I have not yet heard from him. I would like them to tear the engine down a bit more to make a better diagnosis. I don't know if this is going to happen, but if they do not, I will have a worker pull it apart and check the internals. Warranty may not be an option at that point, but for my own mind I would like to know.

    Over the past couple weeks we did have high temperatures, and now that I think of it she did use a bit of oil when I had the heat sheild on. It seems that they cool the engine by blowing air over it toward the ground. This causes the burning of grass below the machine. The shield blocks most of the bottom off so the heat is not allowed to escape from the direction of flow, so must go back over the engine to escape above. So maybe she did drop the level enough.

    I had high hopes of this oil as I know of many stories that are amazing concerning it. One of which involved a company who ran a mower for several days with no oil at all. They forgot to put it in on an oil change and ran for a few days. Some odd sounds provoked them to look into it more to find out there was no oil. No damange. They assume the moly and penatro in it saved the motor.

    I wish the sump was larger as well. Seems odd that the oil capacity on a 27, or even 30 is the same as my 12.5 kaw.

    I ordered a new engine. I get a two year warranty instead of the 90 days with the short block, and do not have to put a guy on it when I could have him working on other needed things.

    If I find out more details on the failure, I will post them.

    Thanks so much for all your contributions gentlemen, you are a great help as always.

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