Mercury Lower Unit

[deerantlers]

I have a 1978 Mercury outboard 40hp (402) that the shift cam went bad. Going to repair later. Trying to buy a used lower unit but just about all have a water spedo that mine don't. I believe you can take the fitting out of the lower unit and use a surface level plug to block it off. The question I have can I do that and will the lower unit mate up to my motor correctly. Lower Unit is a 1643-6458. any help would be appreciated.

 

[fitz73222]

Should not be a problem since the speedo tubing just goes up through a void in the midsection, so no interference. Plug the hole , I think it is 1/8 pipe thread. As for the shift cam, it can break if the engine is shifted into reverse without the engine running or the prop spinning. Just FYI...