I decided not t replace it and instead installed an electromechanical display inside near the electric switches panel. Simply connect it to the alternator.
Did much the same myself, but not sure about which connection on the alternator so connected it to the on/off button on the engine control panel. Obviously not quite so accurate, but as the boat hasn't had a working hour counter since some time before I bought it in 2010 until now, any inaccuracy will help to account for the missing hours.
Mine was fitted inside the cabin on the engine room bulkhead at the top of the companionway, which seemed like a good idea at the time, but fitting it single handed was not easy. So that location is not recommended so far as the actual fitting of it is concerned, but it is easy to read.