Fasteners› Bulk Fasteners

SIERRAMARINE

LOCK NUT

$19.77

SKU: S08C 18-3728

Special Order
Special Order
Ships in 4–6 weeks
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Non-Returnable Item
INSTALL DIFFICULTY
DIY PRO SHOP

Beginner — under 30 min

Description

The Sierra Marine 18-3728 is a lock nut designed for marine engine mounting applications. It features a Unified National Coarse (UNC) left-hand thread type. This lock nut is a replacement for Mercruiser part numbers 11-863332 and 11-99298, as well as GLM part number 19350.

Fitment

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Log your build in the MOTORMIA app and we’ll guarantee this part fits your exact setup — or your money back, return shipping covered.

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Specifications

BrandSIERRAMARINE
Part NumberS08C 18-3728

Buy with Confidence

Built for enthusiasts. Every order is backed by our 30 day return window on eligible items. Unused and uninstalled products may be returned with approved RMA and no restocking fees when received in new condition. Orders placed through the MOTORMIA app with a complete build qualify for our Fitment Guarantee — free return shipping if the part doesn’t fit your exact setup. The guarantee covers fit only; installation must follow manufacturer instructions, and we recommend a qualified shop for parts marked Difficulty 4–5.

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