Perko 0540 Style Replacement Deck Fill Cap, Chrome Plated Bronze, Vented, O-Ring

Overview

The Perko 0540 Style is a replacement deck fill cap range for Perko 0540, 0541, 0556, and 0557 figure deck fill fittings. It gives boat owners a direct cap replacement path when the original gas, diesel, water, or waste cap is missing, worn, hard to seal, or no longer easy to identify at the deck.

The range uses chrome plated bronze cap construction with an O-ring on the vented cap style, helping maintain the deck fill closure in exposed cockpit, side deck, transom, and fuel-fill locations. The gas, diesel, water, and waste options keep the deck fill label matched to the onboard system, which matters during refueling, water filling, and pump-out service.

Key features

• Replacement cap range for Perko 0540 Style deck fill fittings.
• Used with Perko figure numbers 0540, 0541, 0556, and 0557.
• Cap options cover gas, diesel, water, and waste deck fill identification.
• Chrome plated bronze cap construction on the vented cap style for use in exposed marine deck locations.
• O-ring included on the vented cap style to help maintain a proper closure at the fill.
• Gas replacement cap is not for EPA-compliant sealed fuel systems.
• Waste cap is non-vented and does not include a retainer.

Variants

This product is offered in several deck fill cap configurations for matching the cap marking to the boat system it serves.

The cap type changes by variant: gas, diesel, water, or waste. Compatibility with Perko figure numbers 0540, 0541, 0556, and 0557 is consistent across the range.

• 0540DPG99A: Gas cap. This option is marked for gasoline deck fills and belongs to the vented fuel-fill replacement cap style; it is not for EPA-compliant sealed fuel systems.
• 0540DPD99A: Diesel cap. This option identifies a diesel fill point, which helps reduce the risk of confusing fuel deck fills during service or refueling.
• 0540DPW99A: Water cap. This option identifies the freshwater fill, making it easier to separate potable water service from fuel or waste fittings on deck.
• 0556DP099A: Waste cap. This option identifies the waste deck fill for pump-out service; it is non-vented and does not include a retainer.

Compatibility and fit

Before ordering, match the existing Perko deck fill figure or the original cap style to the 0540 Style replacement range. This is especially important on older boats where gas, diesel, water, and waste fills may look similar from above but use different markings or cap arrangements.

For gasoline systems, confirm that the fill is the compatible vented style and not an EPA-compliant sealed fuel system. A sealed system needs the correct cap type for that fill assembly.

Installation and use

Installation is a straightforward cap replacement when the deck fill body is already compatible and in serviceable condition. Clean the threads and sealing area before fitting the new cap, then tighten it securely without forcing it against damaged threads or debris.

This range suits boat owners replacing a lost cap, refreshing a worn deck fill closure, or restoring clear deck fill identification during maintenance. It is especially useful on boats where fuel, water, and waste fills are close together and the cap marking needs to be easy to recognize.

Maintenance and care

Rinse the cap and surrounding deck fill area after saltwater exposure, then check the sealing surface and O-ring condition during routine maintenance. Replace the cap if it no longer seats correctly, if the marking is hard to read, or if the deck fill closure no longer feels secure.