Small Engines (Lawn Mowers, etc.): Mower stalling, carburator, gas cap

Question
"Hi, I have a Honda Harmony HRR216 which starts and runs perfectly until it cuts out after 20 seconds over and over. Does not quit while in choke mode or at very low idle. I cleaned the carb as best I could with carb spray cleaner, but no effect. I can guess that I need to bathe the carb to fully clean it, but am wondering why it starts/runs at all if the carb is truly dirty? Anyway, could you give me tips on carb disassembly and cleaning, as well as how to check for a properly working (ventilating) gas cap. Thanks so much in advance.

Answer
 Hello Eric:

 Gas has Formed Varnish in the Main Jet Passage. This is why it Runs and Quits. The Varnish is Restricting the Gas from Going to the Jet Inside the Carburator. When the Choke is Set, the Engine is Pulling the Gas through the Choke Instead of the Jet. Soak the Carburator Overnight in Cleaning Solution and Then Blow Out All the Ports and Passages with Compressed Air. Send me the Model Numbers Off of the Engine, Please. With these Numbers I can Locate a Breakdown of the Engine and this will Assist you in this Repair. Hope this Helps. Let me know what Happens, Please. Thanks.

 Good Luck

 Respectfully

 John