Re: 1962 Merc 700 gear shift model
Yes, it can be started without the key. Your motor has a magnito ignition. Remove the wrap around shroud, remove the wire from the magnito. Then you will have to jumper the starter solinoid. Leave the control cables and wire connections attached. On that old Merc, thinking you need to put the lower unit in a barrel (no place to hook up muffs). If you are able to start it

touch the wire you removed from mag to shut off/ground the ign.
How long has it been since this engine has been started/run?