The needle on the tacho for my Volvo Penta TMD22 goes to the far side of the dial on turning the key but does not return to zero/rev count.
Periodically the needle shows a rev count after the engine has been running for some time.
Behind the panel there are two black wires connected to a female pin which looks like it should be attached to a male pin, however there are no obvious male pins available. Picture below.
Has anyone had a similar problem or can anyone shed some light?