I have an hour meter for my engine in the middle of my tachometer. It has stopped incrementing when the engine is on. I pulled the tach (which works fine) and all of the four wires that attach to it are well connected. How can I go about troubleshooting this? Is there a common failure mode for these?
The engine is a Westerbeke diesel, a 1973 Four-91. The tach is an aftermarket part from Motorola. The hour meter set into it is analog - it looks like a small odometer.