Re: FUel Tank Vent replacement
The vent fittings come in 2 basic types, straight and 90 degree. When you remove yours notice what type you have and replace with the same. If it's a 90 degree, install it with the tube end up to form a loop in the vent hose, this will help prevent water from entering your tank via the vent. If it's straight, and there is room to install the 90 degree type then do so, it could help to keep it from degrading again.
Also, use stainless steel not z-mack, it will last longer. I have had mud dobbers build nests on the extruded style, but not the recessed fittings. Check your vent line for degrading and if necessary replace with CG approved vent line.