Just replaced the 7 year old impellar on my EV 90 '85 model. They say after a few years of sitting around it is ready to go, worn, dried up etc. Much to my suprise the 7 year old one was perfect looking. Supple, no cracking the arms had a litte curve in them as they conformed to the water pump case. I want to rethink this. Are these impellars made of plain rubber or are they now being made of polyurethane or silicone? It just seems to me that the old one was just fine. Am I wrong or will they last alot longer than 2 seasons.<br /><br />H90