Magnetic Drain Plug 688-45341-10-00 with Gasket for Yamaha Outboard 18-2374 M8-1.25
Magnetic Drain Plug 688-45341-10-00 with Gasket for Yamaha Outboard 18-2374 M8-1.25
Product Overview
Magnetic slot head drain plug and gasket for Yamaha outboard lower units. The plug replaces Yamaha 688-45341-10-00, 688-45341-00-00 and 90340-08M02-00 and crosses to Sierra 18-2374, the thread is M8 x 1.25, and the set ships as one plug with one gasket in a 150 mm x 180 mm x 30 mm bag at 15 g.
The plug is magnetic, so the tip collects the fine steel that the gears and bearings shed in normal service. That is the point of it: a plug with a fuzz of metal on the magnet tells you the gearcase is wearing, and a clean plug tells you it is not.
The gasket is the part that actually seals. A copper or fibre washer that has been compressed once will not seal a second time, which is why the plug and the gasket are sold together and why a drain plug that weeps after an oil change is nearly always a reused washer.
Fitment is broad: these plugs are used across most Yamaha outboards from 40 HP to 300 HP, including the 130, 150, 175, 200, 225, 250 and 300 HP models named on the listing. Yamaha did not use one plug across every gearcase, so buy by part number and compare the old plug rather than by horsepower alone.
Specifications
| Specification | Detail |
|---|---|
| Condition | New / New with tags |
| Type | Lower unit drain plug with gasket |
| Yamaha Part Numbers | 688-45341-10-00, 688-45341-00-00, 90340-08M02-00 |
| Sierra Cross Reference | 18-2374 |
| Replaces | 98-416-08K |
| Thread | M8 x 1.25 |
| Head | Slot head, magnetic |
| Fits | Yamaha outboards 40 HP to 300 HP, most but not all models |
| Quantity | 1 plug and 1 gasket |
| Country Of Origin | Taiwan |
| Net Weight | 15 g including packaging |
| Pack Size | 150 mm x 180 mm x 30 mm |
| Pack Size In Inches | 5.91 in x 7.09 in x 1.18 in |
| Warranty | 3 year |
OEM Cross Reference
| Brand | Part Numbers |
|---|---|
| Yamaha | 688-45341-10-00 |
| Yamaha | 688-45341-00-00 |
| Yamaha | 90340-08M02-00 |
| Sierra | 18-2374 |
| Replaces | 98-416-08K |
Compatible Engines
| Engine | Note |
|---|---|
| Yamaha 40 HP to 300 HP | Most but not all models, check the part number on the old plug |
| Yamaha 130 HP | Lower unit drain plug |
| Yamaha 150 HP | Lower unit drain plug |
| Yamaha 175 HP | Lower unit drain plug |
| Yamaha 200 HP | Lower unit drain plug |
| Yamaha 225 HP | Lower unit drain plug |
| Yamaha 250 HP | Lower unit drain plug |
| Yamaha 300 HP | Lower unit drain plug |
What's Included
| Component | Detail | Qty |
|---|---|---|
| Drain plug | 688-45341, magnetic slot head, M8 x 1.25 thread | 1 |
| Drain gasket | Sealing washer for the drain plug | 1 |
| Fill plug | Not included, order the fill plug separately if needed | 0 |
Signs The Plug Needs Replacing
| What You See | What It Means | What To Do |
|---|---|---|
| Oil weeping at the drain plug | Gasket compressed and reused | Fit the new plug and gasket |
| Metal fuzz on the magnet | Normal wear, use it as a service gauge | Refit and check again next change |
| Heavy metal on the magnet | Gearcase wear, investigate before it fails | Check the gearcase and fit the new plug |
| Plug head rounded off | Slot damaged by a worn screwdriver | Fit the new plug |
| Plug will not tighten down | Thread damaged in the housing | Fit the new plug and check the thread |
| Water in the oil after a service | Gasket not sealing at the drain | Fit the new plug and gasket |
Fitting Notes
| Step | Action |
|---|---|
| 1 | Compare the old plug to the photos and check the part number |
| 2 | Put a tray under the gearcase before removing the plug |
| 3 | Take the plug out and wipe the magnet clean on a rag |
| 4 | Look at what the magnet collected before you refit anything |
| 5 | Clean the sealing face on the housing |
| 6 | Fit the new gasket and plug, hand tight plus a quarter turn |
| 7 | Fill through the top plug until oil runs out of the level hole |
| 8 | Check for weeping after the first run |
Condition & Warranty
| Item | Detail |
|---|---|
| Condition | New / New with tags |
| Warranty | 3 year |
| Packaging | Bagged, 150 mm x 180 mm x 30 mm |
Before You Buy
- Replaces Yamaha 688-45341-10-00, 688-45341-00-00 and 90340-08M02-00
- Crosses to Sierra 18-2374
- Magnetic slot head plug, M8 x 1.25 thread
- Fits most Yamaha outboards from 40 HP to 300 HP
- Sold with its drain gasket
- Buy by part number, not by horsepower
- 15 g with packaging, bag 150 mm x 180 mm x 30 mm
- 30-Day Easy Returns
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Boat Owners' Review
Before You Buy
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