@pbolden. I don't know your specific tachometer but you could have a couple of issues that you can isolate to determine the 'health' of your tach and these generic troubleshooting tips may help.
First, check the ground. 9 times out of 10 a bad ground gets in the way of things working on 12V systems. Have you changed anything? Even something as simple as corrosion on a battery post or putting the battery in for the spring and not tightening the connections is enough.
If you're not 100%, run another separate ground direct from the tach to the negative post on the battery (even a temporary one across the floor for troubleshooting to be sure)
If you're confident the ground is ok, next would be checking the power source. There should be a ignition power that is connected to the tach. First test would be cycling the ignition off/on. Does the tach jump/move at all? If so, you have ignition power. If it doesn't, do the same process but this time use a volt meter to see if you get a reading when power cycling the ignition.
Next, check the tach signal. If the tach isn't getting a signal from the engine it will not operate. With the engine running, again use a voltmeter a measure the signal between the ground and signal terminals on the tach. You should see something in the range of approx. 2V.
If these are both present (ignition and signal), you have a bum tach.
Let us know how this works out.
You have a few options.
First is contact your local Hurricane dealer and get a replacement.
Second is purchase a Faria brand replacement (that's the manufacturer of your existing tach and should connect up the exact same) Here are some examples
Third, is measure the size in diameter of your tach and replace it with a generic tachometer available from most marina or marine supply shops.