Castle LB-23 Diagnostics Manual - Manual (Page 28)

4. Once the Rear Stop is removed, you should be able to fit your arm into the rear of the machine.
Reach in to the rear of the machine and remove the white Muffler from the SQE.
5. Cycle the machine several times to clear out any debris.
6. Inspect the Muffler to ensure that it is also clear of any debris or obstruction.
7. Replace the Muffler and test. If this procedure doesn’t fix the problem then replace the SQE.
Revised 2/9/2007