Small Engines (Lawn Mowers, etc.): McCullough 3516 Chain Saw, air mixture, adjustment screw

Question
Carburator adjustment.  I have to keep the choke partially on to keep the engine running.  There are 3 carb adjusting screws, a green screw labeled L, a red screw labeled H, and a Phillips head screw labeled T.  The O&M manual says to call my dealer, but does not define what each screw does or how they should be adjusted.  I would appreciate some insight on carb adjustment screw functions, initial recommended settings, and troubleshooting adjustments based on symptoms.

Answer
Hello Frank:

First you need to Check the Exhaust Port of the Engine. The Following is a Basic Instruction File for Doing a Diagnostic on the Engine for this Problem. Any Input is Appreciated. **Remove the Muffler and Make Sure the Exhaust Port is Clear. If it is, then Try to Start the engine with the Muffler Off. If it Starts and Runs Properly, then Clean the Spark Arrestor Screen in the Muffler or Replace the Muffler if Required. The Following is the Instruction File for Setting the Air Mixture Screws. Any Input is Appreciated. The Procedure is the Same for 1 or 2 Mixture Screws, Just Use the Instruction File and Skip Over the Section with the Missing Mixture Screw. Now Setting the Air Mixture Screws:  ****Turn the Idle Air (L) and Main Air (H) 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 (H) 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 (T) Screw (Not Idle Air) so the Engine will Stay Running if Required. Now Set the Idle Air (L) Mixture Screw so there is No Hesitation when Throttling from Idle to Full Throttle. Reset the Engine Idle if Required.**** Jenn-Feng Purchased McCulloch in 1999 when they went Bankrupt. MTD Supports McColloch in the US for Jenn-Feng. You can View a Breakdown of this Unit at this Site Addy; http://manuals.mtdproducts.com/mtd/public/list.jsp?BrandCode=10001 and Enter the Model Numbers MT3516 and a Serial Number. The Number  1 is all that is Required for a Serial Number. Then Select the Manual you Wish to View Online. 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. Ratings and Comments are Greatly Appreciated. Thanks.

Respectfully

John