Speedometer not working

[Bduck]

Over a year ago my speedometer on my boat dash quit working. It wasn't a big deal since GPS speed is monitored & more accurate. At first when it quit I found crud plugging the pitot opening but after clearing that it made no difference. So I further let it go not to bother with it until yesterday. I went to the top of the motor where pitot tubing channels in and found it had pulled out real easy. Now I had to remove lower gearcase assy and spacer above that. I found where the tubing broke in to about an inch from pitot itself. Inspection of tubing revealed cracking of the full length of it being routed in channel of motor so I decided to replace a 12' section of the tubing that routed back thru transom and splice into remainder 15' to dash. As I finished this job up I next removed the shroud
between gearcase/spacer & upper motor and found lower engine exhaust housing covered in black soot. This soot has been seeping to outside of painted shroud that covers exhaust housing. I always had to wipe down shroud from a lite film of soot in a couple of places. Today is cleaning exhaust housing and inside shroud.