I have rund B20 without and problem with fuel lines, however, it will be cleaning the fuel system so be prepared to change fuel filters and possibly the screen in the fuel tank.

I really like B100 and I would like to use it all year, but in northwest Ohio it is time to take the temperature into consideration.

If you use B100 will need to change fuel lines and perhaps filter again. (Biodiesel is an amaizing fuel system cleaner.) USE ONLY VITON. I speak from experience of trying other materials that left me along the road with the hoad up and repalcing a replaced line.