[sp949]

On my 1971 1750 Spider, both instruments tend to stick at the bottom end:
the tach will read 1000-1100 with the correct 800-850 RPM idle speed; also, the needle fluctuates between 1000 and 2000 RPM before stabilizing.

The speedometer stays stuck to the lowest point until the car reaches about 25 MPH (my estimation), then jumps to what appears to be the correct speed; if I synch my speed with those police speed billboards that are posted along the road, it seems to be quite accurate.

Do the instruments need any internal cleaning of some sort, or some lubrication at their cable drives? How do I do it, and what oils/grease do I use?

Thanks,
Val in FL

 

[Tifosi]

Sounds like sticky/dirty cables.

Uncouple them at the instrument end and the cable 'should' slide out of the housing. (if not, then the other end needs to be undone)

Clean the cable with kerosene, carb cleaner, gas, or about any type of stuff of that ilk (no brake cleaner!)

Lube it up with lithium grease and slip it back into the sleeve.

Check the sleeves for kinks, sharp bends, and crushed or melted spots.

 

[MyVeloce]

Would this also repair tachs that seem wiggly at low rpms?

 

[Tifosi]

Mechanically driven tachs yes.

Electric drives could be poor/intermittant connections or slightly corroded internal parts.