I have the SA-10XL, which is similar to the SA-1, but also includes heat and water detectors. I bet it has the same fume sensor.
I installed it myself, and I am positive that I remember the warning to install the fume sensor in a location where it won't get wet. If I recall, they recommended at the height of the starter motor, but I cannot seem to locate the owner's install manual. It might be at the boat.
I also know that you have to replace the sensor occasionally, as they tend to wear out I guess. For some reason 5 years seems to stick in my mind.
For what its worth, my old boat had a FireBoy M1R fume detector, and it would go off all the time. Many times a boat going by would be enough to set it off. Maybe it was too sensitive, I don't know, but I am sure it has a lot to do with where you install the sensor.
So far, after a year, I have had no false errors with the SA10XL.
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"Yesterday's Dreams"1995 Carver 325 Aft Cabin 
Posts are amateur opinion only. You assume all responsibility for any action you take as a result of reading my posts.