Sierra 18-3206 Water Pump Housing - Replaces OMC 907774 - I/O Stern Drives 1972-86, Except Cobra

The Sierra 18-3206 is a water pump housing built for I/O stern drive cooling systems covering the 1972-86 model span, except OMC Cobra units, which use a different housing. The water pump housing is the structural body that seats the impeller and directs raw water flow through the drive's cooling circuit, so a cracked, worn, or corroded housing is a common cause of overheating and reduced water flow on affected stern drives. This housing replaces OEM number 907774 and is sold as a single unit per package.

Because fitment on OMC-based stern drives is model-specific, buyers should confirm their drive is not a Cobra unit before ordering the 18-3206 - Cobra applications use a different Sierra part number. Installing the correct housing restores proper impeller seating and water passage geometry for reliable cooling performance.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-3206
• Product Type: Water Pump Housing
• Replaces (OEM): 907774
• Fitment: I/O stern drives, 1972-86, except Cobra models
• Weight: 0.35 pounds
• UPC: 808282113032
• Package Quantity: 1
• Warranty: Limited warranty

Fitment

• I/O stern drives, 1972-86, except Cobra models

Replaces (OEM)

• 907774

Frequently Asked Questions

What does the Sierra 18-3206 water pump housing fit? The Sierra 18-3206 fits I/O stern drives from 1972-86, except OMC Cobra models, which require a different housing.

Does the 18-3206 fit an OMC Cobra stern drive? No. The Sierra 18-3206 water pump housing is specifically excluded from Cobra applications; Cobra stern drives use a separate housing part.

What OEM part number does the Sierra 18-3206 replace? It replaces OEM number 907774 on applicable I/O stern drives, 1972-86, except Cobra models.

How much does the Sierra 18-3206 water pump housing weigh? 0.35 pounds is the weight of the Sierra 18-3206 water pump housing.

How many water pump housings are included when I order 18-3206? One water pump housing ships per package under Sierra part number 18-3206.

Is the Sierra 18-3206 covered by a warranty? Yes, the Sierra 18-3206 water pump housing is backed by Sierra's limited warranty.

What is the UPC for the Sierra 18-3206 water pump housing? The UPC for the Sierra 18-3206 is 808282113032.

What role does the 18-3206 housing play in the cooling system? As the water pump housing, the 18-3206 holds the impeller and directs raw water through the I/O stern drive's cooling circuit; a worn or damaged housing can cause overheating or reduced coolant flow.

Is the Sierra 18-3206 an OEM part or an aftermarket replacement? The 18-3206 is a Sierra-manufactured replacement housing built to meet or exceed the specifications of the original OEM housing it replaces, OEM 907774.

What is the difference between the 18-3206 and a Cobra water pump housing like the 18-4833? The Sierra 18-3206 fits I/O stern drives from 1972-86 except Cobra, while a part such as 18-4833 is built for OMC Cobra lower units (1986-93) without a cone clutch; these are different SKUs, so confirm which drive you have before ordering.

Will the 18-3206 fit any I/O stern drive built between 1972 and 1986? It fits I/O stern drives in that 1972-86 range with the exception of OMC Cobra models, which are excluded from this housing's fitment.