Valiente that is just what I wanted to hear. All I needed to know was that the A4 is fine in conditions where you NEED it (getting out of a moor, lee shore...) and now that I've found a gas sniffer (not cheap but well worth the price) all is well.
I bought a combination gas/propane bilge sniffer several years ago for about $180. I installed the sensor low on the port side of the engine compartment more or less under the fuel pump/filter cup. It did catch a leak once, but I still haven't finished the propane installation (strictly cockpit cookery!)
Now I can face my rebuild with renewed vigor. Oh and Valiente, do you recommend switching to fresh water cooling? What where the advantages for you?
I haven't done this because I am in Lake Ontario and not only do I have a nice cold freshwater lake to run through the A4, I can also use the 180 F T-stat, which gives better combustion. I would recommend a post-water-pump, pre-block "basket" style filter to catch the gruesomes in any situation, including the ever-possible trashed pump vane. I have found some interesting goo in there.
The advantages of FWC in salt are numerous, however, including running anti-freeze as a coolant and the ability to run with that advantageous T-stat (see elsewhere why sea water requires a colder T-stat). I have an A4-owning friend who has taken the A4 to about as far as you can go with his FWC (closed) cooling. Not only does he plumb the heated exhaust water into a pop dispenser cannister (four-five gallon SS pressure dealies you see under the counter at what used to be called "soda fountains") in order to get hot pressurized water, he has an old Lincoln heater block rigged with a fan to get warm air into the cabin in spring and fall! More than I would wish to bother plumbing, but he can use a horde of BTUs that would otherwise just leave the stern.