The ground wire should terminate on the engine block, under the left side
(driver side) intakes. Very hard to see. This wire is brown and is
included in the wire sheath that contains the wires that go to the Hall
sender on the distributor. If your Westy is a Syncro, this wire may
terminate on the oil breather housing, as it does on my 91 Syncro Westy.
To me, it seemed this was not a good place to obtain a good ground, since
the oil breather housing is plastic, and the ground was dependent one of
the four mounting bolts.

When I experienced the same symptoms you are describing, I not only
cleaned up the ground terminal, but fabricated a second wire lead and
terminated it at the base of the distributor to ensure a better ground.

This fixed the problem of running rich for my Syncro Westy.

Good luck.

Michael

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