Keeping dirt out of your fuel during filter changes, choosing the right zinc, and more.

More of this Feature • Part 1: Purifying your fuel filter • Part 2: Clogged relief port, and more
Related Resources • Maintenance Q & A Index • Maintenance Editorial
Elsewhere on the Web • Detroit Diesel

I've been told that there are grades of zinc anodes. Which one should I use for the best protection? R.G., via e-mail

For best protection against galvanic corrosion, use only zincs intended specifically for that purpose. Look for Mil Spec--a military specification standard--Mil-A-1800J stamped somewhere on the zinc. The final letter designation J is the lowest letter permitted for galvanic corrosion protection and indicates that the zinc meets the technical description. When you purchase a new zinc, make sure it has a J or higher letter. If not, or if no specification stamp is present, do not buy it. 

Why must the charging voltage of a battery charger be more than 13 volts? A.S., via e-mail

If the battery charger and the battery have the same voltage, there will be no flow of current to the battery. (In fact, if the voltage of the battery is higher than that of the charger, the battery will discharge.) Most chargers are rated at 13.8 volts, a few at 14 or higher. The greater the difference between the voltages, the greater the current flow, and as battery voltage increases, the rate of charging will slow. Directly after charging, battery voltage may read as high as 14, but this "surface charge" will quickly drop as soon as a load is put on. If no load is present, the voltage will slowly decrease on its own. 

I'm putting down new interior decking, and part of the galley sole is covered with vinyl tiles. Prying them up is quite difficult. Any suggestions? P.G., via e-mail

Set a steam iron to a medium setting and lay a piece of cloth over the tile. Run the iron back and forth across the cloth. As the vinyl and the adhesive heat up, you should be able to pry the tiles up with a putty knife. If the tiles still prove to be stubborn, increase the heat. If a steam iron is inconvenient, use a heat gun.

After you remove the tiles, you may find some surplus adhesive on the sole. Apply hot water to soften it sufficiently so you can scrape it up, or mix one part vinegar to three parts of water and let the liquid sit on the adhesive for at least 30 minutes. This should soften up the glue enough that you can remove it with a wide putty knife. Clean the knife off immediately to prevent the glue from building up.

If there is still some adhesive residue left that you need to remove, try grinding it smooth, but make sure to use safety goggles.

Need help with a maintenance problem? Write to Maintenance Q & A, Power & Motoryacht, 260 Madison Ave., 8th Fl., New York, NY 10016. Fax: (917) 256-2282. e-mail: kkreisler@primediasi.com. No phone calls, please.

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