Overview

The Attwood Marine 66074-3 is a replacement cap and chain for specific Attwood deck fills that use a 1-3/4 inch cap opening, a 3 inch flange, and a 1-1/4 inch straight pipe thread. It closes the fill with an O-ring seal and keeps the cap tethered with a stainless steel beaded chain, which is useful on fuel, diesel, water, or waste fills where the original cap has been lost or no longer seals cleanly.

This is a fit-sensitive replacement part, not a universal cap. It matches the smaller Attwood deck fill pattern used with a 1-7/8 inch deck cutout, a 3-1/4 inch fill neck length, and a 1-1/2 inch I.D. hose. The cap sits flush and uses a slotted opening style, so it is opened with a separate deck fill key.

Key features

• Replacement cap and tether chain for select Attwood deck fill assemblies
• Fits the smaller Attwood fill pattern with a 1-3/4 inch cap opening and 3 inch flange
• 1-1/4 inch straight pipe thread for the matching Attwood fill body
• O-ring seal helps keep the fill closed against water intrusion at the deck
• Stainless steel beaded chain keeps the cap attached to the fill body during fueling or filling
• Flush slotted cap opens with a separate slot-style or 2-prong deck fill key
• Matches Attwood fill bodies built around a 1-7/8 inch installation hole, 3-1/4 inch neck length, and 1-1/2 inch I.D. hose
• Key is sold separately

Compatibility and fit

The quickest way to confirm fit is to measure the existing deck fill before ordering. This cap is for Attwood fills with a 3 inch flange and 1-3/4 inch cap opening. If your fill uses the larger 3-1/2 inch flange and 2-1/8 inch cap size, you will need a different replacement cap.

It is a good match for boats that still have the original Attwood fill body in place and only need the cap and chain replaced. That is common on cockpit, side deck, and transom fill points where the cap sees regular sun, washdowns, and deck traffic.

Installation and use

Installation is straightforward once the fill body size is confirmed. The cap threads into the existing Attwood fill body and seals on the O-ring, so the main job is matching the cap opening, flange size, and thread pattern to the fill already mounted on the boat.

Because the cap is flush and slotted, access is cleaner on walkable deck surfaces than a raised hand-turn cap. On fuel fills, keep the original fill body and bonding arrangement in proper working order and replace this part only on the correct matching Attwood assembly.