How long has the saw been sitting? Check your fuel line for cracking. If the line is cracking your sucking air in the cracks above the fuel. If the line is good then your impulse line might be cracked. (impulse line is the other fuel type line that goes to crankcase to activate the diaphram in the carb to pump, fuel pump). If those are ok then may your filter. If that is ok then if your confident you can remove and replace the carb., take it out and take the side of the carb. apart that has 4 screws. If the diaphram is stiff and not pliable then you need a carb rebuild. If that is good then check your fuel screen on the other side with one screw in the center. Any questions, post and answer like you did, i will check back. Bottom line, your carb is starving for fuel or lack there of. Look and see what brand the carb is. The 2 most common are Tillitson and Walbro.
Luggnutt, February 2012
