how often?
Phil,I also have a 331 but my anodes tend to disolve off before they need to be removed. My diver says they have a bad tendency to just unscrew themselves and fall off as well. How often do you find you need to replace your anode? Mine tend to be 80% gone in 3 months. It seems like a small zinc for this size of boat but no options. Just pulled my engine zinc out of the heat exchanger today because I waited four months.Curious what your experience is.