I remember during discussions on this board, or the old cwbb that a surveyor didn't like it on someones boat. The poster made an agreement with the surveyor that he would replace it every two years to be sure it didn't cause a problem. With all the ethenol in gas today the primer bulbs should be tough enough for diesel. Mine has been in place for a decade with no problems. Squeezing the primer bulb is a lot easier than pushing the pump lever on my engine. I can bleed the entire system with the bulb. One squeeze it probably equivalent to ten pushes on the lever.