click to view larger image

Mercury Mariner 35-250hp Fuel Pump Gasket Kit (OSFPGK857)

Genuine Part # : 21-857005A 1, 18-7817

In Stock
  • Free Shipping


  • 1 YEAR


  • ISO 9001 Certified
    ISO 9001


  • payment payment payment

    Payment Methods

Suits square fuel pumps with inline oil check valve.

This part replaces part #: 21-857005A 1, 18-7817.

This part suits the following engines: Mercury Mariner 35-250hp 2 Stroke 1988-2016.


About The Brand

Outboard Spares brand of parts are tested in Australia's harsh marine environment with a focus on quality and durability. Outboard Spares parts are used by professional fishermen who depend on their parts to stay on the water and in business. So next time you service your engine choose what the professionals use, choose Outboard Spares.

  • Standard Shipping is free on all orders. Oils & Lubricant products can only be sent via Standard Shipping.
  • Express Shipping is $10 flat rate.
  • Pick up is available from our warehouse at 1/84 Brunel Road, Seaford VIC 3198 between the hours of 8:30am to 3:30pm weekdays. You will be notified by email when your order is ready for pick up.

Delivery Time

Orders are dispatched same business day if ordered before 3:00pm AEDT. All orders are dispatched from Melbourne, Victoria and are sent via Australia Post.

For delivery time estimates with Australia Post please use their delivery calculator here:

If you have any questions relating to shipping, please contact us by emailing

Perfect fit

By: on 8 October 2023
My old 40HP 2 stroke Mercury was hard to start, wouldn't idle, and the prime bulb wouldn't get firm... and the engine would flood badly if you tried. Rebuilt the fuel pump and now it starts and runs like a new engine and will idle all day. Rebuilding the pump was straightforward... there's plenty of videos on youtube about it if you need. A better result than one of those dodgy Chinese pumps you can buy online, and the same price.


By: on 29 June 2020
good product

Fuel pump gasket kit.

By: on 8 March 2020
AAA+++ Highly recommended great products great serrvice

Fuel pump gasket kit.

By: on 26 January 2020
Needed help to determine the correct gasket kit for Mercury 50hp Fuel Pump. Supplied serial number as requested and all good. Received kit quickly with tracking emails. Fitted kit today and all leaks gone and running fine. I would recommend outboard spares. Service was great and fast, kit was complete with all I needed and great price.Thanks. Regards Tony.


By: on 11 September 2019
parts arrived in quick time .Fitted to motor and now runs great. Thank you

Write a review