I had to do that for a while.  You will need a hammer and something to
     reach the starter housing that will transmit impact.  I used a piece
     of common metal conduit.

     Place one end of the conduit on the starter top housing, accessible
     through the deck lid.  Give it a stout whack with the hammer.

     Try the starting.

     Sometimes the engagement gear on the starter jams against the teeth on
     the flywheel rather than engaging correctly.  If you rock the critter
     in 4th gear back and forward a bit this will move the ring gear enough
     to avoid the interference that causes the jam.

     If you only get a click and not the whirr the starter relay/"solenoid"
     may not be making the high current circuit.  The whack might help but
     then count on pulling the starter and checking out the attached high
     current relay/"solenoid" or just installing a finely remanufactured
     Bosch (2yr) guarrantee.

     Hope this helps.

     Note that I completely ignore the wailing and gnashing.

     al