Wow..... All news to me, melted prism caps could be another reason why so many of the older Victas bit the dust then..??
When the cap is just above the fuel exit filter and the prism melts like taffy all over it, forming a seal, many owners presume total failure of the machine due to a simple case of fuel not being able to get to the engine!
Little do they know that an $8.00 replacement fuel tap assembly screwed in to the tank, and replacing of the offending cocktail of ehtanol and petrol, with the pure stuff will have it running again.