What is this tube out of lower end

[heyblue]

1979 80HP There is a rubber tube about 1/4 inch outer diameter that comes out of the lower end where the linkage for the reverse lock comes out of the lower end. No water comes out when running on muffs. I am guessing it may be for a speedometer, which my boat does not have. Bought motor used so do not know what it was connected to by the past owner. The tubing is similar to the tube on the engine block to pee hole.

 

[Texasmark]

I don't remember that far back but on newer Mercs, there is a hole in the leading edge of the lower unit and it's the water pickup for the speedometer. It's plumbed from there up to the engine wiring harness where it accompanies the control harness to the helm where it is routed to the speedometer. If the line is not plugged, expect water to come shooting out when underway with no speedometer.

Mark