Speedometers not working

Both my analog speedo and the perfect pass speedo are not working in the boat currently. After reading other peoples problems I did some searching and found that the paddlewheel paddles were all broken off. I ordered a replacement and put the new one in over the weekend. I also used electrical cleaner on the plug to the multi-sensor triducer. Once I installed the new paddle wheel, I spun it with the boat key turned to the "on" spot without the engine running. I expected that spinning the paddlewheel would give me a readout on the perfect pass or the regular speedo, but everything still read 0. So a couple things I guess...

Does the boat have to be in the water for the speedo to work?
Does the boat have to be running for the speedo to work?
If the answer to both of the above questions is "No", then what else should I be looking for?

Hopefully the boat just needs to be running and the next time I put it in the water I'll have a working speedometer, but I thought I'd ask.