Q:How do I know if my start capacitor is bad?
A:Most failures are one of two types:
1."The start cap blew its guts out!" This is what we call catastrophic failure. It is usually caused by an electric motor's starting circuit being engaged too long for the intermittent duty rating of a start cap.
2. The top of it has literally been blown off, and the insides have been partially or fully ejected.Similarly but not quite as dramatic, a start cap may just exhibit a ruptured pressure relief blister. In either case, it's easy to tell that the capacitor is in need of replacement.