Small Engines (Lawn Mowers, etc.): Walbro carb not taking fuel from primer bulb, carburetor body, internal passages

Question
Mac 3227 trimmer with Walbro carb #WT312   D6 . I always ran the trimmer until it was out of fuel to store it in the fall. This spring, the carb won't take gas from the primer bulb. Won't run either except for very short start-up. Is there a check valve in the carb that lets fuel into the engine--both while running & priming?  Thanks for any help.  Jim

Answer
Hello Jim:

There is a Pulse Needle that Usually Sticks and Causes this Problem. You can View a Breakdown/IPL of the Carburetor at this Site Addy, http://69.16.165.8/ and Select Service & Aftermarket. Now Select Aftermarket Parts and Service. Now Select the OEM (Ryobi). Now Select Trimmer. Now Select your Carburetor (WT-340) from the List Provided. Using the Breakdown at the Above Site Addy; the Pulse Needle is #19. This Carburetor has a Primer Check Valve Also. It is #61 and is Just Under the Primer Bulb (#62). If this Carburetor has Never been Cleaned, then I Suggest you 1- Soak and Clean the Carburetor.  The Following is a General Instruction File for Carburetor Cleaning. Any Input is Appreciated. Even though the Carburetor Looks Clean, the Internal Passages May be Restricted with Varnish that Gas Causes to Build Up over Time. I Suggest you Make Sure the Gas is Free Flowing to the Carburetor Inlet Port. If the Gas is Free Flowing to the Inlet Port, then  **Remove, Disassemble and Soak the Carburetor Overnight in Carburetor Cleaner (I Use Gunk). I have Found that Most People can Use a Breakdown/IPL and Disassemble the Carburetor Enough for Proper Cleaning. You Only have to Remove the Bowl (if Applicable), Float Pin (if Applicable), Float (if Applicable)  and Needle Valve and Any Adjustment Screws that Go Into the Carburetor Body. The Welch Plugs Do Not have to be Removed. Then Soak the Carburetor Body and Parts in a 1 Gallon Can of Gunk Carburetor Cleaner Overnight. The Can has a Parts Tray Inside it for the Small Parts. Once the Carburetor and Parts are in the Cleaner, you can Replace the Lid for Safety and to Prevent Accidental Spillage. Then Blow Out the Passages with Compressed Air.*** (Do Not Use High Pressure Air for the Zama Carburetors, they have Check Valves for the Primer and these are Usually Blown Out of the Carburetor if Not Careful. Allow the Zama Carburetor to Set on a Drip Pan and Dry)***. Install New Parts if Required.** 2- Check and Clean the Exhaust Port. Remove the Muffler and Inspect the Exhaust Port for Carbon Blocking the Exhaust Port. Check the Muffler and Spark Arrestor Screen (in the muffler) for Carbon Blockage Also. If you Hit a Snag or this Does Not Correct the Problem,  I am Here if You Require More Assistance. Hope this Helps. Let me Know What Happens, Please. May the All Mighty Bless You and Yours. Thanks.

Good Luck

Respectfully

John

PS: I am Allowed to Answer 10 Questions a Day. If you See I am Maxxed Out, then Try Submitting your Question at or Just After 8pm EST (US). My New Day Starts then. Thanks.

Respectfully

John