fitting smiths impulse tachometer.

[mesrine]

Hi, I have fitted a NOS smiths 4 cyl impulse tacho to my 1967 mini cooper. its a positive earth car, so I have removed the neg side coil lead which go's to the distributer, and inserted the pulse lead into place re-making the circuit... the clock itself, I have wired in and earthed as per instructions.....But, the tacho appears to read double all the time, ie tickover is around 2000, and this seems consistant up the scale as I am increasing my revs. the gauge is not erratic at all, and measures steady all the time, its just too high......Just wondered if anyone has any ideas or views on this.

cheers ray

[Lord Croker]

If this is a fairly old tachometer, it may be adjustable. I have an old Smith's tacho & at the back, there is a hole, (usually covered by a label or piece of tape) through which you can access a regulating screw, rather similar to what you find on old style clocks.

[mk1]

Yup, If its a 60's one it should have an adjustment hole as described.

M

[mesrine]

this is a smiths 4 cyl , pulse rev counter...code KP 1250/00

there is no adjustment hole ?

also have original instructions, nothing about adjustment/calibrating is mentioned.

regds ray