I just found some old gauges and have a questionabout this tach. I have looked all over the net and have found different ones. However what is the deal with the key and switch? Any help would be greatly appreciated. Thanks In advance...
On the tach there is a separate redline pointer that moves and locks at the highest RPM that the engine ran on the last pass (dragstrip). The key resets the pointer back to the original position, usually 5000 rpm, and can then record the next passes max RPM. The removable key prevents the driver from altering the recorded RPM. - think of a hired driver blowing the engine because of over-reving - now car owner has proof of the deed. Terry
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