Re: hose that covers shift cable where it goes through transom
i assume your talking about the shift cable bellows as there's no hose that covers the shift cable, just the shift cable bellows. go get the service manual if you don't have one from the adults only sticky at the top of the i/o fourm. you'll need it as yer getting ready to tear into it a little ways. it's not straight fwd. as to how to go get to it.
you need to remove the bellhousing from the boat to replace this bellows.
basicly, remove the drive, disconnect the shift cable inside the boat, remove the hing pins, remove the bellows (three of them, main, exhust and shift cable), and water hose. the s/m explains the exact procedure to do these things. once the bellhousing is in your hands you can slide a new shift cable bellows onto the shift cable.
if you've never done any work to the shift cable or bellows, nows the time to do some PM on other items too since your right there. some items to replace are the shift cable and it's bellows, driveshaft bellows, water hose. also inspect ujoints and lub them, lub the coupler, check alignment, check gimble brg. for total smoothness.... i'm sure there's more to do that i've forgot to mention, but this is a start..