Small Engines (Lawn Mowers, etc.): Repairing 21cc Craftsman weedwhacker, air fuel mixture, screw out

Question
Hi,

My engine needs to be injected with fuel on the carb venturi before it starts, and even if it does, it dies in a few minutes.

How to set the carb properly?

Thanks,
Vic


Answer
 Hello Vic:

 The Air/Fuel Mixture Screw are Set as Follows: Turn Both Low and High Fuel Mixture Screws In until they Bottom Out. **DO NOT JAM THE SCREWS**  Back Each Screw Out 2 Turns. This will get it Started and Running. If it has No Power, then Turn the Main Jet Screw (High) 1/4 Turn in and this Should Give Power back to the Trimmer. If the Trimmer Still Starts and Stalls, then the Carb needs to be Cleaned and Overhauled. Check the Exhaust Port and Muffler Also. The Exhaust Port and Muffler will Build up Carbon Deposits and Slowly Stop Up the Muffler and the Exhaust Port. There is A Screen in Most Mufflers called a Spark Arrestor Screen. This Screen will Also cause the Problem you are having if it Becomes Clogged. Hope this Helps. Let me know what Happens, Please.

 Good Luck

 Respectfully

 John