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Perko Flush Caps

Perko Sea Strainer Flush Cap

Perko Sea Strainer Flush Cap

Regular price $40.00 USD
Regular price Sale price $40.00 USD
Sale Sold out


All size cap orders are currently shipping within 24 hours!


Available in three sizes to fit any Perko Model 493 series Sea Strainer.  Makes flushing and winterizing your raw water cooled boats easier than ever!

These Flush Caps make descaling with Barnacle Buster, fresh water flushing, and winterizing your raw water cooled equipment a breeze! No need to constantly remove your hoses to gain access to your strainer, as you can simply swap the stock cap for ours, remove the strainer basket, and use a standard garden hose to flush or winterize your engines, generator, or air conditioners. Temporarily replacing your strainer cap allows you to effortlessly flush your strainer and adjoining system with minimal effort.

These Flush Caps are constructed of a durable, impact resistant, pressure-molded rigid plastic. The gaskets are custom made silicone, and are more chemically resistant than the stock rubber gaskets. The 1/2", 3/4", 1", and 1.25" (small and medium) sizes have a 3/4" NPT thread fitted with a ABS swivel head female garden hose fitting.

The Small (1/2" & 3/4" hose) sized caps are typically used for most marine air conditioning water intakes and generators up to approximately 8KW in size.

The  Medium (1" and 1.25" hose) size is standard on most gas motors up to 8.2 liters in displacement. 

The Large (1.50"-2" hose) caps are made threaded in 1" NPT and come with a ABS swivel head female garden hose fitting installed. We also include a 1.25" hose adapter for convenience. This is to accommodate the greater water flow requirements of larger diesel powered vessels. These fittings utilize 1.25" ID hose such a standard bilge pump hose which can be economically sourced at your local marine supply or hardware store (Lowe's and Home Depot). Alternatively the installed garden hose fitting can be used for fresh water flushing.

If you purchase a cap with any other size cap a $10 discount will be applied to the pair during checkout.



Small Cap (1/2" and 3/4"): Bolt spacing is 2 7/8" center to center, Cap diameter is approximately 2.5"
Small size cap is used for most A/C units and generators up to about 8KW.

Medium Cap (1" and 1.25"): Bolt Spacing is 3.75" center to center, Cap diameter is approximately 3.5"
Medium caps are used on most all gas motors up to 8.2L and some larger generators, or strainers feeding multiple A/C units

Large Cap (1.5", 2"): Bolt Spacing is 4.5" center to center, Cap diameter is approximately 4.25"
The Large caps are used on diesel powered boats typically. 

IMPORTANT NOTE ON LARGE SIZE CAP: The 493/500 series 2.5" strainer uses the same size cap as the 1.5-2" models, HOWEVER the top strainer casting is different than the next sizes down and there is not sufficient clearance for the cap to seal properly due to minor interference at the hose fitting location. We are working on a one off solution for this size and will update the site product listings once testing is complete and it is available for purchase. 

 Tips for Use:

1. Don't overtighten the wingnuts on the strainer bolts. The silicone gasket is softer than the stock rubber and it doesn't take much force to form a seal. Overtightening can result in the plastic flexing and the seal not having equal pressure along the rim of the strainer. 

2. Whenever you are flushing with fresh water from a garden hose with sufficient pressure be sure to leave your seacocks OPEN. When closed you risk potentially breaking the globe on your strainer. Having the seacock open also allows you to backflush the salt water out of the line from the through-hull fitting. The engine water pump draws less water than the hose is delivering so there is little risk of bringing in seawater so long as you have flow from your hose.

As always please feel free to reach out if you have any questions or issues and we will make sure you are taken care of.  



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