Small Engines (Lawn Mowers, etc.): John Deere GX345, ring gasket, fuel tank cap

Question
I just recently purchased a 2003 john deere gx345. The problem that I am having is when the engine gets warmed up and I try to idle down the engine the motor just wants to rev up and down. The engine will idle normally when I first start it up. The engine is a Kawasaki 20 HP liquid cooled motor with 98 hours on it. My first thought would be a problem with the fuel pump but would like some "Professional" advice.  Thank You in advance Chad

Answer
Chad

You have what they call surging Engine idles roughly, unevenly, or surges.
Possible causes:

  1. Carburetor is dirty.
  2. Air leak in carburetor or intake manifold (e.g., bad O-ring, gasket, primer).
  3. Carburetor is improperly adjusted or needs service.
  4.  Fuel line or fuel tank cap vent is clogged.
  5. There is water in the fuel.
  6. Fuel pump is defective.
  7. Governor is not set properly, sticking, or binding.
  8. Carburetor needs adjustment or service.
  9. Loose carburetor/intake pipe resulting in vacuum leak.

These are some reasons that your engine is doing that so check these one at a time and then restart to see if that will fix the problem.