How to Modify Stihl 039 / MS390 Chainsaw Muffler & adjust Carburetor - Shredder II

Stihl chainsaw 029/290, 031/310, 039/390 dual-port muffler modification and how to remove the "limiter tabs" on the carburetor air/fuel mixture adjustment screws. Plus... instruction for super-tuning the Carb on most modified Stihl chainsaws. Increased speed and torque means less work, improved fuel/air flow means less heat... This is a must do for any mid-range saw that&used on a regular basis.... Now, that&how it should be.