ryobi petrol chainsaw problem with fuel ?

Check the primer bulb itself for any small hole or split that may allow air in, check also fuel lines for the same. Deprnding on type of carb there is usualy a fine gauze in the fuel flow under the diaphragm cover which may have got blocked. One sign of this is the primer bulb is reluctant to pop back out due to the restriction. Hope this is of use

smudge1966
May 2015