Im confused. Are you saying you pull on the cord but it wont budge? If so likely seized. Try removing the spark plug and giving it a couple of pulls (Put a small drop of oil in the spark plug hole first). OR are you saying the cord doesn't want to move but does anyway? Could be a rusty recoil spring (Remove the starter and replace the spring or lube the old one up if its still OK with a little axle grease or the engine could be partially seized (In this case pour a 40/60 mix of diesel and auto trans fluid down the spark plug hole to penetrate the rust and get it moving again). If this is the case obviously it is best to hone and replace the piston but the diesel/ATF fluid will get it going to rule out any other problem aswell.
Either way more info needed to advise the best solution. I always start with the simplest fix first - remove the starter and inspect the spring then remove the spark plug and pull the cord. THEN remove the head and inspect the bore/piston and decide whether or not to attack the rust inside.
All really depends how it was stored, in what climate you live in and how the machine was maintained prior to you getting it/fixing it, and if you can be bothered.
Hope this helps. Would be interested to see how you get on.
