Small Engines (Lawn Mowers, etc.): stihl 021 carburetor, carburetor body, stihl 021

Question
hi, purchased 2nd hand 021. wouldnt run or idle good so removed carb and reassembled. now sparkplug wet and wont start and also crankcase fill with petrol after leaving saw for 4 days . i drained everything and useing dry sparkplug restarted saw and adjusted jets . then next day saw all petrol wet again.
 What does the impulse tube that runs from tank into jet rubber houseing has that an adjustment? also the high jet has a yellow plastic to covering that prevents removing and turning more than one turn..

Answer
rob

The reason for the yellow plastic is for epa or smog control. What your problem is the carburetor float is either adjusted wrong or the Needle seat is bad. Thus letting fuel drain in to the engine intake and it is flowing to the cylinder and then in the oil. 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, Float Pin, Float 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. Install New Parts if Required. ****All the Carburetor Adjustments are the Same for chain saws and Trimmers. There are Several Location for the Air Mixture Screws. The Idle Air Mixture Screws are Usually Located at the Top of the Carburetor Bowl and the Top of the Carburetor Body. If the Main Air and Idle Air Mixture Screws are Side by Side on the Side of the Carburetor, then the Idle Air is the Farthest from the Engine. The Main Jet Air Mixture Screw is Located in the Bottom of the Carburetor Bowl or Beside the Idle Air Screw on the Side of the Carburetor Body. Some of the Older Model Carburetors have the Main Jet Mixture Screw Straight in from the Top of the Carburetor Body (this is Rare anymore). If you have Cleaned the Carburetor (Disassembled and Soaked Overnight in Carburetor Cleaner (I Use Gunk). Then Blow Out the Passages with Compressed Air and Install a New Kit if Required. Now Setting the Air Mixture Screws:  ****Turn the Idle Air and ****Main Air Mixture Screws In Until SNUG **Do Not Jam** Then Reverse Both Screws 1 1/2 Turns. Holding the Throttle Full Open, Start the Engine. Turn the Main Air Mixture Screw Clockwise Until Proper Revs are Obtained. Occasionally you May have to Turn this Counter Clockwise to Achieve the Proper Revs. Now Allow the Engine to Idle. Set the Engine Idle Screw (Not Idle Air) so the Engine will Stay Running if Required. Now Set the Idle Air Mixture Screw so there is No Hesitation when Throttling from Idle to Full Throttle. Reset the Engine Idle if Required.**** Will the Saw Start and Quit if you Pour a Small Amount (1/2 oz) of Fuel Mix Into the Carburetor Throat and Try to Start the Engine. If it Starts and Quits, then the Carburetor is the Cause of this Problem.