- Brand: Mercury
- Size: 65 HP
- Color: Black
- Style: 3 Cyl
- Condition: Used
- Notes: Freshwater - Inspected & Tested
- SKU: 23510 LRU
- Manufacturer Part Number: 6038A20 4931A8 4814A8 6038A10 4931A28
- Country of Manufacture: United States
- Motor & Engine Type: Mercury
- Part Type: Motors, Engines & Components
- Surface Finish: Painted, Black
- Warranty: 1 Year
- Inventory Number: 23510 LRU
- Website Category: Lower Units
- Website Sub Category: Complete Lower Units
- UPC: N/A
- Shipping: $50.00
Mercury Long Lower Unit Square Shift Shaft 3 Cyl
Mercury Long Square Shift Shaft 3 Cyl lower unit for 1972–1975 outboards, 65 650 HP. Inspected, serviced, and tested for proper function. Gears are replaced only if bad — good OEM gears are retained. Please note: There are holes in cultivation plate where a whale tail was attached. There are some scuffs and scratches in the paint. The skeg on this lower unit has been ground down some, but this will not affect the overall performance of this unit. This does not come with the trim tab.
SPECS
| Driveshaft length: 21″ | |
| Driveshaft splines: 11 | Prop shaft splines: 13 |
Driveshaft length measured from the top of the water pump.
WHAT WE DID
| ❖ Pressure checked to 12 PSI ❖ New water pump impeller installed ❖ Driveshaft and prop shaft checked straight | ❖ Shifts smoothly through gears ❖ Professionally cleaned ❖ Opened and inspected |
FITMENT
Mercury Long
| Years | 1972–1975 |
| Shaft | 21" |
| Horsepower | 65 650 HP |
Verify by model and serial number before purchase to confirm this is the correct unit for your application.
Backed by Southcentral Outboards. Warranty validated by core return — we provide the shipping label. Failures during normal use within the warranty period will be repaired or replaced.
DISCLAIMER
Listing info accurate to the best of our knowledge but not guaranteed. Fitment is the buyer’s responsibility — verify by model and serial before purchase.
SOUTHCENTRAL OUTBOARDS · ALTAMONT, IL

