Small Engines (Lawn Mowers, etc.): honda Harmony mower, ring gasket, fuel tank cap

Question
Dear Ben,

 I have a Honda Harmony, Model #  HRB216TDA Mower with a Type GCV160  OHC/OHV  engine.  The plugs and filter are new. Starts on the first pull. The engine, after starting runs in a sing -song manner ( with a up and down running noise) To make it run smooth, I have to push the throttle lever past the fast position, partly into he choke position. This corrects the choppy running.  Is there any simple adjustment I can make, or is it ready for a Tune-up?

Thank you.
Sincerely,
Tom


Answer
Tom
Problem: 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.

Problem: Engine operates erratically, surges, and runs unevenly.
Possible causes:

  1. Fuel line or fuel tank cap vent is clogged.
  2. There is water in the fuel.
  3. Fuel pump is defective.
  4. Governor is not set properly, sticking, or binding.
  5. Carburetor needs adjustment or service.
  6. Loose carburetor/intake pipe resulting in vacuum leak.