JT, go to motor. Your speedo hose should attach internally to a small opening on front of lower unit. Find that little hole. Run you a small wire into that to check for clog and all it takes is a tiny piece of trash. Then find where that small rubber hoe goes into motor from boat. You might have to pull cowel. There should be a hose barb connection somewhere in that area. Disconnect that hose and blow back toward motor. That should clear any clog. Don’t blow back toward speedo.