Description

Mercury MerCruiser 18411A2 is a genuine OEM upper gear set for Alpha-family sterndrives. Current Mercury dealer references identify it as an upper gear kit with 22/20 teeth and a 1.50/1.47 ratio, used in the upper drive gear section rather than as a general lower-unit gear set.

Key Features

• Genuine Mercury MerCruiser OEM part number 18411A2.
• 22/20 tooth upper gear set.
• 1.50/1.47 gear ratio.
• Current dealer listing shows GTIN 745061123625.
• Current dealer shipping specs are approximately 4.90 lb, 7.30 in. x 4.80 in. x 4.60 in.

Engine Compatibility

The strongest supportable fitment for 18411A2 is MerCruiser MC-I, R, MR, Alpha One, and Alpha One Gen II sterndrives with serial coverage shown as 0K999999 and below, across model years commonly listed from 1971-1997. This is a drive application part, so the sterndrive family matters more than the engine model alone.

Serial Number Fitment Notice

Verify fitment by exact drive model, serial number, and the correct driveshaft housing / drive gears parts diagram before ordering. This gear set spans several older MerCruiser Alpha-family drive applications, so serial-based confirmation is the safest way to match the correct ratio and tooth count.

When This Part Needs Replacement

This gear set is typically replaced during upper-drive rebuilds when the original gears are worn, chipped, pitted, noisy, or damaged from gearcase failure. Because 18411A2 is the matched upper gear set, it should be selected by the correct ratio and drive family rather than by appearance alone. This is a practical service inference supported by its documented upper-gear-kit application.

Installation Notes

Install 18411A2 only after confirming the correct Alpha-family drive application and ratio requirement. Current parts references place it in the driveshaft housing and drive gears section, so it should be matched to the exact upper-drive gear layout during rebuild or reseal work.

Alternate/Superseded Part Numbers

Current cross-reference sources connect 59832A2, 18410A2, and 59832A4 as earlier superseded OEM numbers associated with 18411A2.

Parts Desk Insight

With Alpha gear sets, the important match is the exact ratio, tooth count, and drive family. A quick serial-number and ratio check usually saves a lot of trouble, especially on older MC-I, MR, Alpha One, and Gen II drives where several gear sets can seem close on paper.

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