Small Engines (Lawn Mowers, etc.): Sears leaf blower model 358.797931 wont start, gas mixture, air bubbles

Question
Hello John,

Thank you in advance for helping us hobbyists who like to fix things. My Sears leaf blower, 24cc 2-Cycle, model 358.797931 will start and then stop. I was using it fine for about 15 mins and stopped for lunch and it never start again regardless of pressing the prime button. To get it to start, I removed the air box cover and put in 1-2 cc of gas mixture into the carburetor with the throttle fully open. It will now start and run for 2 seconds and stop as if it is not getting fuel from the carburetor. When I prime the bubble sometimes I see tiny air inside the fuel line moving towards the carb so I think the fuel filter is fine. The unit is about 3 years old and I only used it no more than 10 hours a year. I’ve read a forum that you suggested to check the exhaust that might be blocked due to carbon build up. I then took the muffler out, primed and started the engine, but the result is the same. I took to carb apart and it looked clean. The two diaphragms on the white plastic block seem fine with no tear. I used a tiny wire through all 3 tiny holes for fuel feed and there is no blockage. I put them back and no difference (start then stop). I just don’t understand how it goes from running fine to not running at all within 20 minutes apart (after lunch). Can you please advice? Is there other thing like the ignition system might shut down after start?

Best Regards,
Tham.


Answer
 Hello Tham:

 Unless the Carburetor has Bleed Back to the Tank, you shouldn't See Air Bubbles in the Fuel Line. If this Unit is 3yrs Old and has the Original Filter, then Change the Filter. Check the Fire at the Plug. The Coil May be Bad and Firing Just enough for the Start, Run and Shutoff Cycle. Remove the Plug and Watch the Fire when Pull the Recoil. Does it Fire the Entire Time the Engine is Turning? Other than the Coil, Blocked Exhaust and Low Compression; the Carburetor is the Only Other Possible Cause for the Problem you Described. I'm Not a Fan of Using Wire and Spray Cleaners on the Carburetors. I Suggest you Soak the Carburetor Overnight in Gunk Carburetor Cleaner and then Blow out the Passages with Compressed Air. Always Install New Kit. The Diaphragms May be Stretched and Not Pumping the Fuel. You can View a Breakdown/IPL of the Carburetor at this Addy http://walbro.com/ and Select the Service and Aftermarket Tab. Then Select Aftermarket Parts and Service. The Select the OEM (Poulan). Then Select Blower. Then Select the WA-228A Carburetor. This will Download a Breakdown/IPL of the Carburetor. Hope this Helps. I am here if you Require more Assistance. Let me know what Happens, Please. Thanks.

 Good Luck

 Respectfully

 John