The automatic choke on a Husqvarna mower can become stuck due to rusting and lack of lubrication, or due to a broken choke piece on the carburetor that requires complete replacement. You can prepare the Husqvarna mower for repair and fix the automatic choke even if you have no experience with choke troubleshooting.
The choke on an engine serves to regulate air intake into the motor to allow the engine to start under different conditions, and is controlled via a lever on the mower. The choke is not typically used when the engine is warm and recently in use, but the "Full Choke" option is often selected when starting the engine from a "cold start." A cold start occurs when the engine is completely cold and not recently used. It is normal for an engine to struggle to ignite in such a condition, but the use of the choke on the motor serves to alleviate this problem. The parts integral to the choke's operation exist on the engine's carburetor.
Choke Rod Rusting
Rust can build up on the choke rod on the engine's carburetor naturally over time, requiring lubrication. Rusting can also occur through little use or through improper storage. Consistently failing to store a mower in a sheltered area during rain storms will greatly speed the process of rusting. Additionally, storage areas should always be cool and dry to prevent the rusting process.
Choke Piece Failure
Sometimes, lubrication will not be enough to fix a stuck choke. The choke part may be too rusted to salvage, requiring complete replacement. Outside of rusting issues due to rain and improper storage, aspects of the choke system can become otherwise worn and damaged to the point of failure due to natural wear and tear over time.
You can repair the choke problem by opening the Husqvarna mower's engine hood and locating the carburetor halfway up the left side of the Husqvarna mower's Briggs & Stratton engine. The circular choke piece is connected to the carburetor via a metal linkage rod. Spray WD-40 along the choke part and the metal linkage rod to lubricate the chain. Test the engine. Removal of the bolts holding the circular choke piece in place will be necessary if the WD-40 was not enough to unstick and fix the choke. Remove the bolts with an adjustable wrench and pull off the carburetor. Position the new choke into the spot on the carburetor where the old choke was placed. Reinsert the choke bolts to secure the new choke to the carburetor and close the mower's engine hood.