Clicking and clucking I know but clacking is a new concept for me...
I guess that your machine makes a clicking sound when you go to start it.
Probably the sound of the starter solenoid that you usually don't get to hear because the engine is turning over and the click noise is drowned out.
If the starter is not turning the engine over there may be several reasons - defective starter - seized engine - poor electrical connection to it - battery not fully charged.
If the machine has lights turn them on and have somebody tell you if they dim when you try to start up. If they stay bright without any dimming then the starter motor is not taking current. If they do dim then the starter motor is trying to work but the battery is too weak. A seized engine is the very last thing you should consider - most unlikely.
Good luck...
April 2015