240V requires 2 hot wires (each 120V of opposite phase). The others are neutral (used for 120V loads such as an oven light), and ground.
That jumper should be removed when using a 4 wire cord (properly connected of course). It's connected for a 3 wire cord.
Also, it's a good idea NOT to reply below someone's signature. good newsreaders don't automatically quote things after the sig separator, making replies to that difficult.