Sierra 18-3773 Prop Nut - Replaces 90171-16011-00, 95307-16900-00 - Fits Yamaha 20-30 hp (1980 & Up)

The Sierra 18-3773 Prop Nut is a replacement propeller nut engineered for Yamaha outboard motors. It secures the propeller onto the propeller shaft, keeping it correctly seated and preventing it from working loose under load. This prop nut is built as a direct replacement for the Yamaha OEM parts it corresponds to, so it installs using the same fit and thread engagement as the original hardware it is replacing.

This part is designated for Yamaha outboards in the 20-30 hp range, covering motors from 1980 and up. Because prop nuts are a wear item that can loosen or corrode over time from constant water exposure and vibration, keeping a correct-fit replacement on hand or in your spares kit helps avoid losing a propeller on the water. The 18-3773 ships as a single prop nut, ready to thread onto the propeller shaft during a routine propeller swap or hardware replacement.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-3773
• Product Type: Prop Nut
• Replaces (OEM): 90171-16011-00, 95307-16900-00
• Fitment: Yamaha 20-30 hp (1980 & Up)
• Weight: 1 pound
• UPC: 808282312107
• Item Dimensions (L x W x H): 8 x 6 x 4 inches
• Quantity: 1 prop nut per pack

Fitment

• Yamaha 20-30 hp outboards (1980 & Up)

Replaces (OEM)

• 90171-16011-00
• 95307-16900-00

Frequently Asked Questions

What does the Sierra 18-3773 prop nut fit? The Sierra 18-3773 prop nut fits Yamaha outboard motors in the 20-30 hp range, covering models from 1980 and up.

What OEM Yamaha part numbers does the 18-3773 replace? It replaces Yamaha part numbers 90171-16011-00 and 95307-16900-00.

How much does the 18-3773 prop nut weigh? The Sierra 18-3773 prop nut weighs 1 pound.

Is the 18-3773 a genuine Yamaha part or an aftermarket replacement? It is a Sierra-brand aftermarket replacement made to match the fit of Yamaha part numbers 90171-16011-00 and 95307-16900-00, not a Yamaha-branded OEM part.

How many prop nuts come in one package? The 18-3773 is supplied as a single prop nut per pack.

What is the UPC for the Sierra 18-3773 prop nut? The UPC listed for the Sierra 18-3773 prop nut is 808282312107.

Will this prop nut work on a 25 hp Yamaha outboard from 1985? Yes, the 18-3773 covers the Yamaha 20-30 hp range for motors from 1980 and up, which includes a 1985 25 hp model.

What are the shipped dimensions of the 18-3773 prop nut? The item dimensions listed for the Sierra 18-3773 prop nut are 8 x 6 x 4 inches.

Do I need any special tools to install the 18-3773 prop nut? Installation involves threading the prop nut onto the propeller shaft in place of the original Yamaha nut, the same way the OEM 90171-16011-00 or 95307-16900-00 nut installs; no special part-specific tooling is called out for the 18-3773 beyond standard prop-removal tools.

Is the Sierra 18-3773 the same part as Sierra 18-3709? No, the 18-3773 and 18-3709 are different Sierra prop nut part numbers with different OEM cross-references and different Yamaha fitment, so they are not interchangeable.