its the o ring that goes
Generally yes, I've changed quite a few.
However, it could also be a broken primer line in behind the panel. If that is the case, obviously a different repair is required, and simply locking the primer in would not necessarily fix it.
If we're discussing what defects are acceptable for dispatch of an aircraft which does not have an approved minimun equipment list, the answer is actually no defects (save for the ever mentioned burned out nav light for day flying).
Private pilots flying simple aircraft on routine flights should not be dispatching with undispositioned system defects. If the maintainer declares and placards a system inoperative in accordance with an approval, and dispatches the aircraft, that's fine. I very much doubt that a maintainer is going to dispatch an aircraft with a fuel system leak...
In the absence of written (log book or placard) disposition of a defect, the pilot who flies a defective aircraft is taking all of the responsibiliy upon him (or
her (see "fraternity"!)) self. What will you the pilot say, when the authority asks after the "event"; "Mr./Ms. pilot why did you fly the aircraft with the known unservicability?". Unless your answer is "to fly all of these women and children away from that tornado to save their lives", you might be answering more questions you don't like!