In the store it is convenient that various sizes are prepared even those which are difficult to obtain. Although it deteriorates because it is a rubber part, it can be changed regularly because it is cheap. Vibration isolation was the most important.
I replaced the mechanical fuel pump electromagnetically, but the operating sound came to reach the room through the frame, wearing anti-vibration rubber and saw it. There was a tremendous effect beyond expectation, and I did not hear any sound at all.