While you wait for answers, we may have found some information which could help you.
Click here for Oil Gas RatioMcculloch 2818 Runs fine but spool will not spin?
McCulloch MT270X ignition coil?
how to change mcculloch sl trim head?
How can I replace electric cord on mcculloch air stream electric blower?
Fuel Starvation?
How do i keep my strimmer running?