I have a manual that must have been written before my engine was made.
My LD28 has rounded ribs on the block which from what I have been lead
to believe is a later model one.

The injection pump drive gear has three marks an "A" mark, a "B" mark
and a "dot". The book I have eliminates the "A" mark as it is for LD20
engines. BUT as it doesn't even mention the possiblity of a "B" mark
which one should I use? Anyone know?

Phil