I can vouch that all of the rubber parts that I had on my Yanmar were heavy duty and 1st quality. This includes the Yanmar mounts, water pump impeller, and hoses. My Yanmar mounts and hoses were 20 years old when replaced as maintenance items. No apparent defects at the time. Recommended replacement of the pump impeller was 600 hours. It would come out looking new. I wouldn’t give it a second thought based on my experience.