Mercury Water Pump Screw 74191

Mercury MerCruiser 74191 is a genuine OEM screw sized .312-18 x 3.250. Current Mercury dealer references list it as 10-74191 Screw (.312-18 x 3.250) and show it superseded to current replacement part number 8M0204669. It is commonly used in MerCruiser sea water pump service, including pump body / impeller kit applications where this screw secures the pump assembly.

Key Features

• Genuine Mercury Marine OEM part number 74191 / 10-74191.
• Current replacement part number is 8M0204669.
• Size listed by Mercury as .312-18 x 3.250.
• Current dealer listing shows GTIN / UPC 745061175501.
• Current dealer shipping specs are approximately 0.06 lb, 3.50 in. x 0.50 in. x 0.50 in.
• Current Mercury kit references show this screw used in 46-807151A14 water pump body and impeller kit contents.

Engine Compatibility

The strongest supportable fitment for 74191 is MerCruiser sea water pump service, especially applications using the plastic one-piece body sea water pump found across Alpha engines with closed cooling and internal pump, Bravo, Ski, Inboard, 330 B-W TR/TRS, and high-performance engines without a solid plate front mount, as shown in the Mercury water pump body and impeller kit reference.

Serial Number Fitment Notice

Verify fitment by exact engine or drive serial number and the correct sea water pump / pump body parts diagram before ordering. This screw is a specific size and application hardware item, so serial-based confirmation is the safest way to match the correct water pump fastener and current replacement number.

When This Part Needs Replacement

Replace this screw when the original is corroded, rounded, seized, stretched, missing, or removed during sea water pump service and no longer suitable for reuse. Since this screw is part of the pump-body fastening hardware, correct thread, length, and condition matter during impeller or pump-body reassembly.

Installation Notes

Install 74191 or current replacement 8M0204669 only after confirming the correct MerCruiser sea water pump layout. Current Mercury kit contents list this screw with the water pump assembly, O-ring, impeller, quad ring, wear plate, and related washers, so it should be matched to the exact pump stack during service.

Alternate/Superseded Part Numbers

Current Mercury references show 8M0204669 as the active replacement for 74191 / 10-74191.

Parts Desk Insight

With sea water pump hardware, the important match is the thread size, length, and pump-body layout. A quick parts-diagram check helps avoid mixing this 3-1/4 inch screw with shorter pump screws used in the same service area.

Shipping: Ships same or next day for fast Canada wide shipping.