Lesson's from Ethanol's Freshman Year

[tsubaki]

I cut open a piece of 5/8 USCG approved hose the same type of the 3/8 you got (pretty red stripe and all) and the interior is lined with the same material as the grey hose.
I know one thing the black hose really absorbes the heat from sunlight. While installing some yesterday at about 80 degrees laying on the deck the hose was too hot to hold in your hand, next to it was the grey and it was as cool as the deck.