First thing is I do when I bring in a saw is blow it off. If it runs, but won't stay running, ill start sprayin carb cleaner around the intake areas and carb base. If nothing there then I pop in fresh gas, check fuel fliter, pop in a new plug. Then nothing better, ill try and adjust it a lil. If its going to smoothe out ill toss the saw aside till the next day. Try again, if it is good, i send it out...
Tell ya the truth, it isn't very often I get air leaks, The occasional crank seal, occasional intake boot, pulsar lines are more common. Rest of the time its a fuel line or a carb problem...
I'd charge $18 labor at work to toss in a kit. Bring it to my house and its $10