New mantis worked perfectly last season. Stored it for the winter. Tried to start it this spring. Pull cord is frozen up. Can't pull it out.

First, call Mantis and get their advice. It may be covered under warranty (I believe it comes with a 2 year warranty). If not under warranty remove the spark plug and try to pull the starter rope. If you can pull it out squirt a little 2-cycle oil in to the spark plug hole and pull it out several times before reinstalling the plug. Then try to start it again. If you can't pull it out after removing the plug try removing the engine cowl that contains the starter rope and see if you can pull it out then. If you can't then there is something wrong with the starter rope mechanism. Try some oil or Liquid Wrench on the spring to see if you can free it up. If you can then the piston may be seized. Again, squirt a little oil ni the spark plug hole. Take a ratchet wrench and socket to put on the crankshaft nut. Try to turn it. Do not apply to much force. I would send it back to Mantis for repair or replacement unless you are mechanically proficient enought to take the engine apart. If you have been using the correct fuel/oil mixture this should not happen.