Small Engines (Lawn Mowers, etc.): JD LA 140, clean filter, fuel inlet

Question
I have a JD LA140 about 2 years old with 38 hours on the engine. It has recently started to backfire and stall under load. I do the maintenance eg. clean deck, clean filter, lube bearings, change belts etc. The fuel pump puts out a solid flow of spurts, I have not touched the carb.

Answer
I would start by removing, dis-assembling and cleaning the carburetor with compressed air from an air compressor and carburetor cleaner.  Blow air through all the  carb orfices.  Do not blow too much air through the fuel inlet...you want to avoid blowing out the inlet need seat.

The non-adjustable carbs used today are very sensitive to any slight dirt or debris.  Carb cleaining is the most common repair we do these days.

Let me know if the carb cleaning fixes your problem.
Eric