There's not a whole lot you can do with those older motors where the wiring enters one side and the fuel enter the other. It's a stupid design. Newer motors (Yamaha started around '91) have the eletrical harnesses, fuel line, oil line and control cables all enter on the same side of the cowling so an adapter can be used to connect the rigging hose to the cowling like so:
I've seen where the hose shown above was used with those older motors, but a cap needed to be installed and then cut open so the rigging could run to separate sides of the engine. Looked like hell in my opinion. I think your best bet will be to use something simple like this flexible sleeve.
http://www.thmarine.com/products/Riggin ... x-Sleeving
Given what I see on the Mako below, it looks like there should be a few clips to keep that fuel line tight to the bottom cowling. If you are missing those, they are probably still available through your local dealer. Get 'em and wrap everything in the flexible stuff.