I would use thick wall high temperature viton hose 5/16 ID from McMaster.com.
5119K891 (Same as 5119K89) for the 1/8" wall thickness
I bought some just in case this exact hose started leaking, but I have not had to use it yet.
The Viton hose is not as physically tough as the OEM rubber compound, but it should last longer in the chemical environment. Just take care not to grab it with rough or sharp pliers, and take care positioning the hose clamps so they press evenly on the hose - not digging in with the edge.
You can only buy 2' or larger sections, and it is expensive. But it is the only option I have.
You might try going to a diesel service center, such as Caterpillar for 5/16" or 8 mm ID hose. Or even NAPA. If it is not diesel rated fuel line it will not last long at all.
Dan