Sierra E-TEC Drain Screw 18-4255, Replaces 309243, Fits 40-50 HP Cobra Drives (1989-97)

The Sierra E-TEC Drain Screw, part number 18-4255, is a replacement gearcase drain screw engineered for outboard motors using Cobra Drives rated 40-50 HP (1989-97). It directly replaces OEM number 309243, making it a straightforward swap when the original screw is worn, stripped, or lost during a gear lube service.

The screw uses an Allan head design, allowing it to be driven with a hex key for a secure fit and reliable removal during routine gearcase maintenance. Sierra manufactures this drain screw to meet or exceed the specifications of the original equipment part it replaces, and it is backed by Sierra's standard customer satisfaction warranty. This is a compact, low-weight component intended for gearcase oil drain and fill points where a dependable, properly sized screw is essential to prevent leaks.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-4255
• Head Style: Allan Head
• Weight: 0.01 pounds
• Product Dimensions: 0.39 x 0.39 x 0.39 inches
• UPC: 808282200411

Fitment

• 40-50 HP (1989-97)
• Cobra Drives

Replaces (OEM)

• 309243

Frequently Asked Questions

What does Sierra part 18-4255 fit? Sierra 18-4255 is designed for outboards with Cobra Drives rated 40-50 HP (1989-97).

What OEM part number does this drain screw replace? The Sierra E-TEC Drain Screw 18-4255 replaces OEM number 309243.

What tool do I need to remove or install this screw? An Allan (hex) key is required, since the 18-4255 drain screw uses an Allan head design rather than a slotted or Phillips head.

How much does the 18-4255 drain screw weigh? This drain screw weighs 0.01 pounds.

What are the dimensions of the Sierra 18-4255 drain screw? The Sierra E-TEC Drain Screw measures 0.39 x 0.39 x 0.39 inches.

Is the Sierra 18-4255 an OEM part or aftermarket? 18-4255 is a Sierra aftermarket replacement part, manufactured to meet or exceed the specifications of the original equipment drain screw it replaces (OEM 309243).

Does this drain screw come with a warranty? Yes, the Sierra 18-4255 E-TEC Drain Screw is covered under Sierra's standard customer satisfaction warranty.

When would I need to replace this drain screw? Replace the 18-4255 drain screw when the original gearcase drain screw on a 40-50 HP Cobra Drive outboard is worn, stripped, or lost during a gear lube change.

What is the UPC for Sierra 18-4255? The UPC for the Sierra E-TEC Drain Screw 18-4255 is 808282200411.

Is the 18-4255 the same as OEM 309243? Sierra 18-4255 is a direct replacement for OEM part 309243, engineered to the same fit and function.