66M-24410-11-00 835389T1 Mechanical Fuel Pump Assembly for 4-Stroke Outboards, Compatible with Yamaha F15 T9.9 and Mercury Mariner 8-15 HP, Replaces ref 835389A2

66M-24410-11-00 835389T1 Mechanical Fuel Pump Assembly for 4-Stroke Outboards, Compatible with Yamaha F15 T9.9 and Mercury Mariner 8-15 HP, Replaces ref 835389A2

Which pump is this?

MECHANICAL LOW-PRESSURE DESIGN: This engine-mounted diaphragm pump uses a plunger, diaphragm, return springs and check valves to move fuel from the boat tank toward the carburetor, matching the official Yamaha FUEL exploded view for this part family. It is not an electric in-tank pump, not the water-cooled revised pump used on early standard F9.9 models, and not the high-pressure EFI pump. Similar-looking pumps from other Yamaha families are not interchangeable.

Signs yours is due

REPLACE THE COMPLETE PUMP: Intended as a complete-pump replacement for symptoms such as a primer bulb that will not stay firm, fuel starvation or stalling above part throttle, temporary recovery while squeezing the primer bulb, external seepage or gasoline in four-stroke engine oil after the fuel path has been checked. The package contains one fuel-pump assembly only; fuel filter, hoses, clamps, mounting bolts, gaskets and repair-kit parts are not included unless pictured by the seller.

Will it fit?

COMPATIBLE FITMENT: Compatible with select Yamaha F15 and T9.9 high-thrust four-stroke outboards listed in official Yamaha catalog records for the 66M-24410 family (catalog years 1998-2007), and select Mercury or Mariner 8-15 HP carbureted four-stroke models listed for 835389A2 and 835389T1 by serial range. Match the original pump number and engine serial or PID before ordering. Not for standard F9.9 models, not for two-stroke engines and not for electric high-pressure fuel systems.

Every row is from this SKU fitment workbook. Match the number stamped on the pump you remove. Same horsepower name shipped different pumps.

OEM and swap numbers

VERIFIED PART-NUMBER CHAIN: Replaces ref 66M-24410-00-00, 66M-24410-01-00, 66M-24410-10-00 and 66M-24410-11-00, plus Mercury 835389A2, 835389T1 and kit number 835389T02. Catalog-supported aftermarket references include 18-35302, 9-35302, PAF15-07140000, 1-32-66M24410 and 1399-39549. Do not treat 825470 as a catalog-verified replace until the original pump number is matched. Do not use 18-35303 or 18-35304 as a cross-reference for this pump family.

Wrong part

If the number on your old pump is not in the table above, this is the wrong pump.

What ships

One complete mechanical fuel-pump assembly. No hose, no filter, no bolts, no carburetor, no rebuild kit.

Install

INSTALL WITH SERIAL-NUMBER DISCIPLINE: Work in a ventilated area away from ignition sources, label the inlet and outlet hoses, compare the check-valve order and port orientation with the removed pump, renew damaged seals, use the engine manual's fastener torque, prime the line and inspect for leaks. Mercury applications are separated by official serial-number ranges; if the old pump number cannot be read, send the engine model or serial number and a photo of the original pump before purchase.

FAQ

Q: Will it fit a standard Yamaha F9.9? A: Official Yamaha catalog records list this pump on the F15 and the T9.9/FT9.9D high-thrust family only. Standard F9.9 models were cataloged with a different pump. Confirm your original pump number before ordering.

Q: Is 18-35303 or 18-35304 the correct replacement? A: No. Published catalogs map those numbers to different pump families.

Q: My Mercury is a 9.9 — will it fit? A: Match by serial-number range. Official Mercury records list this pump on specific 8/9.9/13.5/15 HP carbureted ranges only.

Q: Will it replace 825470? A: Official Mercury Where Used lists 825470 as a superseded number on some 8/9.9 serial ranges. Local handbook PDF has not yet confirmed that cross-reference, so match the original pump number or send a photo before ordering.

Q: Is this electric or water-cooled? A: No. It is an engine-driven mechanical low-pressure diaphragm pump.

Please note

Aftermarket fuel pump by GHMarine. Not affiliated with the engine brands named above. Confirm the number on the removed pump, the engine model, and the serial range before you order. This page is the pump only, not a multi-part kit.