2 x Lower Unit Oil Seal 26-821928 for Mercury Mariner Outboard 6 8 9.9 10 15 HP
2 x Lower Unit Oil Seal 26-821928 for Mercury Mariner Outboard 6 8 9.9 10 15 HP
Product Overview
Two lower unit oil seals for Mercury and Mariner outboards from the 6 HP motor up to the 15 HP. They replace Mercury 26-821928 and cross to Sierra 18-0585 and GLM 85560, and they ship as two seals in a 150 mm x 180 mm x 10 mm sleeve at 21 g.
The seal sits at the propeller shaft where the shaft leaves the gearcase. It keeps the gear lube in and the water out, and it is the part that fails first on a motor that is used in salt water or left in the water between trips.
A failed seal does not usually leak oil where you can see it. It lets water into the gearcase instead, the lube turns milky, and by the time the gears whine the damage is done. That is why the seals are worth changing as a pair while the lower unit is apart.
Fitment covers the Mercury and Mariner 6 HP, 8 HP, 9.9 HP, 10 HP and 15 HP outboards in both two stroke and four stroke form. The maker fitment also lists the Force 6 HP to 25 HP range on this seal, so check the model or the serial number before ordering.
Specifications
| Specification | Detail |
|---|---|
| Condition | New / New with tags |
| Type | Lower unit oil seal, propeller shaft |
| Mercury Part Number | 26-821928 |
| Sierra Cross Reference | 18-0585 |
| GLM Cross Reference | 85560 |
| Fits | Mercury and Mariner outboards, 2 stroke and 4 stroke |
| Fits Horsepower | 6HP to 15HP |
| Also Listed For | Force 6HP to 25HP |
| Package Contents | 2 x oil seal |
| Net Weight | 21 g including packaging |
| Pack Size | 150 mm x 180 mm x 10 mm |
| Pack Size In Inches | 5.91 in x 7.09 in x 0.39 in |
| Warranty | 3 year |
OEM Cross Reference
| Brand | Part Numbers |
|---|---|
| Mercury Marine | 26-821928 |
| Sierra | 18-0585 |
| GLM | 85560 |
Compatible Engines
| Horsepower | Models |
|---|---|
| 6 HP | Mercury and Mariner, 2 stroke and 4 stroke |
| 8 HP | Mercury and Mariner, 2 stroke and 4 stroke |
| 9.9 HP | Mercury and Mariner, 2 stroke and 4 stroke |
| 10 HP | Mercury and Mariner, 2 stroke and 4 stroke |
| 15 HP | Mercury and Mariner, 2 stroke and 4 stroke |
| Force 6 HP to 25 HP | Listed on the maker fitment, confirm the model |
What's Included
| Component | Detail | Qty |
|---|---|---|
| Lower unit oil seal | 26-821928, propeller shaft | 2 |
| Gear lube | Not included, refill with the maker grade | 0 |
| Gasket set | Not included, this listing is the seals only | 0 |
Signs The Seal Has Failed
| What You See | What It Means | What To Do |
|---|---|---|
| Milky gear lube on draining | Water past the prop shaft seal | Fit both new seals |
| Oil sheen behind the motor | Seal lip worn, lube escaping | Fit both new seals |
| Gear lube needs topping up each trip | Seal leaking under load | Fit both new seals |
| Rust on the prop shaft behind the seal | Water sitting against the seal | Fit both new seals and clean the shaft |
| Whine from the gearcase | Water has reached the gears | Fit both new seals and inspect the gears |
| Seal lip cracked or hard | Age and heat | Fit both new seals |
Fitting Notes
| Step | Action |
|---|---|
| 1 | Drain the gear lube and check it for water before starting |
| 2 | Remove the propeller and the prop shaft hardware |
| 3 | Take out the old seal with a seal puller, do not score the bore |
| 4 | Clean the seal bore and polish the shaft where the lip runs |
| 5 | Coat the new seal lip with gear lube before fitting |
| 6 | Press the seal in square and fully seated, lip facing the lube |
| 7 | Refit the hardware, refill with the maker grade and check the level |
| 8 | Pressure test the lower unit if you can, then run and recheck for leaks |
Condition & Warranty
| Item | Detail |
|---|---|
| Condition | New / New with tags |
| Warranty | 3 year |
| Packaging | Sleeve, 150 mm x 180 mm x 10 mm |
Before You Buy
- Two seals in the pack, sold as a pair
- Replaces Mercury 26-821928
- Crosses to Sierra 18-0585 and GLM 85560
- Fits Mercury and Mariner 6HP to 15HP outboards, 2 stroke and 4 stroke
- Also listed for the Force 6HP to 25HP range, check the model first
- Propeller shaft seal for the lower unit gearcase
- 21 g with packaging, sleeve 150 mm x 180 mm x 10 mm
- 30-Day Easy Returns
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Before You Buy
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