Mercury Mariner Shift Shaft Bushing Assembly - 23-43052A4
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The Mercury MerCruiser Quicksilver 23-43052A4 is a genuine Mercury Marine OEM shift shaft bushing assembly used in select Mercury and Mariner outboard lower-unit gearcase assemblies. This assembly supports and seals the shift shaft area where the lower unit shift rod passes through the gear housing. It helps maintain proper shift shaft alignment while sealing the gearcase against water intrusion and gear-lube leakage at the shift shaft opening.
Key Features
- Genuine Mercury Marine factory OEM bushing assembly.
- Mercury/MerCruiser part number: 23-43052A4.
- Manufacturer part number: 43052A4.
- Official part label: BUSHING ASSEMBLY.
- GTIN/UPC: 745061149786.
- Listed shipping weight: 0.13 lb.
- Listed shipping dimensions: 2.25 in. L x 2.25 in. W x 1.25 in. H.
- Used in select Mercury/Mariner lower-unit gearcase shift shaft sealing and guide locations.
Application Compatibility
Common where-used application groups include select Mercury and Mariner outboards by serial number and gearcase configuration, including:
- 40 Jet applications where specified
- 45 Jet applications where specified
- 45 Bodensee 4-Stroke applications where specified
- 50 HP 3-cylinder applications
- 50 HP FourStroke / BigFoot / EFI FourStroke applications
- 55 HP and 60 HP 3-cylinder applications
- 60 HP BigFoot and 60 EFI FourStroke applications
- 65 Jet and 80 Jet applications
- 75 HP, 80 HP, and 90 HP 3-cylinder applications
- 75, 90, 115, and 125 DFI 1.5L 3-cylinder applications where specified
- 75, 80, 90, 100, and 115 EFI FourStroke applications where specified
- 100 HP, 115 HP, and 125 HP 4-cylinder applications where specified
Use this assembly only where the Mercury/Mariner lower-unit or gearcase diagram specifically calls for 23-43052A4 / 43052A4.
Fitment Notice
Confirm fitment by engine serial number, lower-unit gearcase style, shift shaft configuration, and exact Mercury gear housing diagram before ordering. Similar horsepower engines can use different shift shaft bushings, seals, O-rings, and retaining hardware depending on production range and gearcase design.
When This Part Needs Replacement
Replace this bushing assembly if the shift shaft area is leaking gear oil, allowing water into the lower unit, causing milky gear lube, or failing a pressure/vacuum test. It should also be replaced if the bushing housing is cracked, the internal seal is worn, the O-ring is flattened or damaged, or the shift shaft has excessive play during lower-unit service.
Installation Notes
Inspect the shift shaft surface, bushing bore, O-ring sealing area, lower-unit casting, and related gearcase seals before installation. A worn or corroded shift shaft can damage the new seal and cause repeat leakage. During gearcase service, also inspect the driveshaft seals, propeller shaft seals, drain and vent screw gaskets, water pump base, and pressure/vacuum test results before returning the lower unit to service. Follow the Mercury service manual for the correct installation procedure and fastener torque for the specific gearcase.
Alternate/Superseded Part Numbers
- 23-43052A4 — Mercury/MerCruiser formatted part number
- 43052A4 — Manufacturer part number
- 23-43052A1 — earlier kit reference to verify by serial number and diagram
- 23-43052A2 — earlier kit reference to verify by serial number and diagram
- 23-43052A3 — earlier kit reference to verify by serial number and diagram
- Sierra 18-2358 — aftermarket cross-reference
- GLM 21024 — aftermarket cross-reference
- Mallory 9-76139 — aftermarket cross-reference
- SEI 98-205-05K — aftermarket cross-reference
Parts Desk Insight
The shift shaft bushing area is one of the common gearcase leak points because it sits above the gear housing and seals a moving shaft. If gear lube is milky or the lower unit fails a pressure/vacuum test, inspect this assembly along with the driveshaft, prop shaft, and drain screw sealing points rather than replacing only the most visible seal.
Shipping: Ships same or next day for fast Canada wide shipping. ⚓
Shipping information
In-stock and OEM parts: ship same or next business day.
Locally warehoused items: ship within 3–4 business days.
Special-order items: timeline confirmed after order.
Returns & warranty
Returns & Satisfaction Guarantee
We stand firmly behind the quality of every product we sell. Your confidence matters to us — and we back it with a straightforward 30-Day Satisfaction Guarantee.
If you are not fully satisfied, you may request a return within 30 days of delivery. All returns must receive pre-approval prior to being sent back. Unauthorized returns will not be accepted.
To qualify for a return:
Item must be in new, unused condition
Product must be in its original packaging
All parts, components, hardware, manuals, and accessories must be included
Packaging must be undamaged and suitable for resale
Important:
Electronics are strictly inspected. No returns on open-box electronics. Exceptions may apply only with prior written approval. Any electronic unit that has been installed, powered, activated, or altered may not be eligible for return.
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