Mercury Mariner Lower Unit Gear Housing Seal Kit - 26-43035A4
Free returns on all eligible orders
You have 30 days to request a return. All sale items are final sale.
The Mercury MerCruiser Quicksilver 26-43035A4 is a genuine Mercury Marine OEM lower unit gear housing seal kit for select Mercury and Mariner outboard gearcases. This kit is used during gearcase resealing service where the factory lower-unit diagram calls for 43035A4 / 26-43035A4, helping renew the sealing points that keep gear lubricant inside the housing and help protect the lower unit from water intrusion.
Key Features
- Genuine Mercury Marine factory OEM gear housing seal kit.
- Mercury/MerCruiser part number: 26-43035A4.
- Manufacturer part number: 43035A4.
- Official part label: SEAL KIT Gear Housing.
- GTIN/UPC: 745061149670.
- Listed shipping weight: 0.28 lb.
- Listed shipping dimensions: 7.00 in. L x 8.00 in. W x 1.50 in. H.
- Intended for lower-unit gearcase resealing service where the Mercury parts diagram specifies this kit.
Application Compatibility
Listed fitment includes select Mercury/Mariner 100 HP, 115 HP, and 125 HP 2-cycle outboards with the applicable gearcase configuration.
Common listed application context:
- Mercury/Mariner 100 HP 2-cycle outboards
- Mercury/Mariner 115 HP 2-cycle outboards
- Mercury/Mariner 125 HP 2-cycle outboards
- USA serial number 0B209468 and newer
- Belgium serial reference 9523034
- Gearcases with either 3-jaw or 6-jaw reverse clutch where specified by the factory diagram
Use this kit only where the Mercury/Mariner gear housing diagram specifically calls for 26-43035A4 / 43035A4.
Fitment Notice
Confirm fitment by engine serial number, horsepower, gearcase style, and reverse clutch configuration before ordering. Mercury used different lower-unit seal kits across similar mid-range outboards, and the correct kit depends on the gear housing assembly, not horsepower alone.
When This Part Needs Replacement
Replace this seal kit when servicing water intrusion, milky gear lube, gear oil leakage, driveshaft seal leakage, propeller shaft seal leakage, shift shaft leakage, or after a failed gearcase pressure/vacuum test. It is also the correct service approach when resealing the gear housing during lower-unit overhaul or major gearcase repair.
Installation Notes
Inspect the driveshaft, propeller shaft, shift shaft, bearing carrier, water pump base, seal bores, drain and vent screw seats, and related gasket surfaces before installing the new seals. A grooved shaft, corroded seal bore, damaged carrier, or worn water pump base can cause repeat leakage even with new seals installed. After assembly, pressure/vacuum test the gearcase before refilling with gear lubricant and returning the lower unit to service.
Alternate/Superseded Part Numbers
- 26-43035A4 — Mercury/MerCruiser formatted kit number
- 43035A4 — Manufacturer part number
- 26-43035 — related individual upper driveshaft oil seal reference; verify by diagram before substituting individual components
Parts Desk Insight
A complete gear housing seal kit is usually the better choice when the lower unit has water-contaminated oil or fails a pressure/vacuum test. Replacing only one visible seal can miss leakage from the shift shaft, prop shaft, carrier, drain screw washers, or water pump base area, so the gearcase should be inspected as a complete sealing system.
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.
We are serious about product integrity — and equally serious about taking care of our customers. If there is ever a product issue, contact us immediately so we can make it right.
For return authorization, please contact our support team before shipping anything back.