My 91 ranger has a cracked filler hose too. About 6 years ago i used some 3M sealant (looks like tar) to fix my cracked hose. I had to smear the sealant onto the hose with my fingers. It's a tight reach but i got enough on to seal the cracks. It needed 2 layers to fix it. Let it cure for a few hours before topping off the tank.

Go to your local boat marina to look for your rubber hose. They usually have an assortment of hoses for outboard motors.

Good luck.