Need help with my outboard jet foot install

[RedfireSVT]

i have a 2004 90hp yamaha 4 stroke and i need help with my jet drive install. i have a small black tube that runs down from the front of the outboard into the lower unit on my prop but there is nowhere to install this on the jet foot. i'm not even sure what this tube is but it screws into the prop lower unit just in front of the water pump housing. can anyone tell me what this is and how do i install it on my jet lower unit?

here is where it comes out of the motor:

here it is going into the lower unit on my prop just in front of the water pump housing:

nowhere to install it on my jet lower unit:

 

[RedfireSVT]

i believe it's for the speedo (which my boat doesn't have) so i'm just gonna leave it out.

 

[Lil' Blue Rude]

Could have been for a water pressure gauge. :?:

 

[fishbum]

Speedo.