Stihl Chainsaw Troubleshooting Guide

4. If saw runs but, not on gas in tank, check gas tank for old gas. Empty old gas and, look for syrup in the bottom of the tank, if present clean thoroughly. Use carburetor cleaner, gas and a brush that can reach in and not melt. Try to start with fresh gas mix.

Stihl Chainsaw Carburetor Troubleshooting Chart

Hard Starting, Will not idle, Rich Idle