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Captain O-Ring – Boat Deck Fill Cap O-Ring Seal Gaskets for 1.5” Cap OD for Gas, Water, Waste, Diesel (5 Pack)

4.8 (5) Write Review
Free shipping on orders over $29.99

$13.85

$ 6 .47 $6.47

In Stock

About this item

  • Replacement o-ring seal gaskets for marine fill caps with 1.5” thread OD (1.5” outside diameter at the cap threads).
  • Commonly found on boat deck fill caps for gas, disel, water, waste, and more. Confirm that your cap has a 1.5” outside diameter at the threads to confirm fitment.
  • Package includes five (5) o-ring seals. O-Rings measure approximately 1.5” inside diameter (1-1/2”), 0.14” Thick (slightly over 1/8”), and 1.8” Outside Diameter (slightly over 1-3/4”).
  • Molded from heavy duty Buna Nitrile rubber for long lasting durability and resistance to gasoline, diesel, fuel treatments, etc.
  • Manufactured and warrantied by Captain O-Ring LLC. Proudly assembled in the USA!


Restore the air tight and water tight seal on your deck fill caps with Captain O-Ring’s replacement marine deck fill cap o-rings. Designed to fit deck fill caps with a 1-1/2” thread OD (outside diameter at the cap threads). These o-rings feature an inside diameter of approximately 1-1/2”, a thickness of just over 1/8”, and an outside diameter just over 1-3/4”. Important: Make sure to measure your fill cap before ordering to confirm the dimensions above match it. Molded from heavy duty Buna Nitrile rubber, these deck fill cap o-rings are impervious to gasoline, diesel, and fuel treatments while being safe for contact with water and waste. Package includes five (5) o-rings. Replace your old, worn, leaking o-ring and have spares on hand for the future. Manufactured and warrantied by Captain O-Ring LLC. Proudly assembled in the USA!


Claudia W. McCann
Reviewed in the United States on April 6, 2025
Too thick.
Anxioustattoedandbookish
Reviewed in the United States on July 1, 2024
Bought for a 1972 Sea ray. 1.5" diameter is good but the thickness is almost double the stock O-ring causing my caps to sit proud.-Check the O-ring thickness before ordering
Gary L.
Reviewed in the United States on June 16, 2024
Perfect fit and no leakage. Great price too.
Charles D Collver Jr
Reviewed in the United States on May 5, 2024
Caps stand a little proud because the o-rings are a bit thicker than the originals.
JTWILCOXSON
Reviewed in the United States on November 29, 2024
great buy