I bought a GT5000 with the Kohler 25hp engine in 2005. The first engine leaked oil through oil gasket, smoked and backfired terribly.
Sears replaced the engine under warranty. The second engine had the same problems after 6 months. Called Sears and I was told the engine was a replacement part and had a 90 warranty. So much oil leaked and collected that one of the many backfires caught it on fire and almost burned down my garage.
The melted plastic parts alone where over $700 so I went the re manufactured route recommended by the service tech. Finished the 2010 mowing season and the start of 2011 all three issues are back. Hot oil shoots on your left foot when it warms up, runs all round the frame then drips all over the garage floor.
The recommended shut down procedure works 70% of the time so I mow with a fire extinguisher he hand. Again told it was a 90 warranty on replacement parts.
Monetary Loss: $1049.