Re: fuel pump

Posted by HH56 On 2024/5/10 16:08:04

That hole is probably an air breather or relief hole above the diaphragm and a leak there would tend to indicate an issue with the diaphragm. Possibly it was too tight and has developed a split or crack. This can happen if the two halves were screwed together and diaphragm was clamped down without the arm being held against the spring so diaphragm was at its maximum or full stroke when tightened. Another possibility is if it was an old NOS pump or one rebuilt with an NOS original rubber rebuild kit Ethanol or some other additive in modern fuel has destroyed the diaphragm.