Mercruiser hoses

[sogood]

Doing some improvements and replacing hoses is on the agenda. The boat has sat up for some time and some of the hoses don't look as healthy as I'd like. I was checking out the hoses on the manifolds and the two large hoses that run from top down are different, in that one seems to have a hard spring insert which you can feel when you squeeze the hose, whereas the other just depresses, with no obvious insert. Is there an insert or is this just a build up of some sort of debris/crud.

Thanks in advance.

 

[Bondo]

Ayuh,.... Welcome Aboard,.... Whatcha workin' on,..?? Merc has built millions of motors over the years,.....

 

[sogood]

Sorry, it's a Mercruiser 5.7 circa 1990 with an Alpha Gen 1 outdrive.