MGB starters do have pinions with different numbers of teeth, I know you
have to watch out for this if fitting a modern geared starter, so maybe it
is possible (I don't know whether it *is* physically possible) that yours
was rebuilt with the wrong one. The inertia starter (MGB to 67) uses 9
teeth, the pre-engaged (after that) uses 10, so easy to check. FWIW the MGC
and factory V8 also use 9 teeth, the latter despite being pre-engaged.
To free it rock it back and fore in *4th* (no 1st) gear, or sometimes you
can turn the square shaft on the back of the motor to free it.
Hunt's Eighth Law: "If you haven't found a use for something yet you haven't
kept it long enough".
----- Original Message -----
> How do I determine if I have the correct gear on the starter? I got a new
> (used) starter for my motor (1964 1800cc) and had it rebuilt and it could
> perhaps have the wrong gear. Were the gears specific to the MGB motor, or
> were all series "A" starter gears/rings the same?