My STX38 would run but under high rpm with the mower engaged, the more restrictive fuel filter would starve the carb of fuel. I had a few other new filter and the least restrictive one worked better but not perfect. That's when I talked to John Deere and they immediately said it was the fuel filter. I think they charged my 6 bucks and it's been running great ever since. The STX38 has the fuel tank up high. Kohler Command 12.5 hp. Great engine.
