Q: How do you replace a fuel filter on Mercury Zephyr?
A: Fuel filters are paper replacement type and can be found screwing into carburetor fuel inlet or in fuel line. Ensure engine is cold, sat for at least 3 hours. Collect necessary tools, including appropriate replacement filter, wrenches for flare nut fittings on carburetor-mounted filters, or screwdriver and pliers for in-line types. Have clean rags ready to catch spilled fuel. Remove air cleaner assembly, note positions of vacuum hoses if disconnected. Follow fuel hose from fuel pump to locate filter. For carburetor-mounted filters, use wrench to hold nut, loosen fitting, and disconnect fuel line. Move line for better access, unscrew fuel inlet filter nut, and replace filter, gasket, and spring. Hand-tighten fuel inlet fitting into carburetor, then fully tighten using two wrenches. For screw-in type carburetor filters, remove clamps, hose, and filter, then hand-start new filter and fully tighten. Cut new fuel hose, position spring clamps, and attach to filter and steel fuel supply line. For in-line filters, remove clamps and hoses, cut new hoses, install clamps, and attach to filter, metal supply line, and carburetor inlet fitting. After installation, run engine, check for leaks, and reinstall air cleaner assembly, reconnecting hoses to original positions.