Thermostat Housing Gasket 688-12414-A1 18-0844 for Yamaha 75 115 150 200 225 HP Outboard
Thermostat Housing Gasket 688-12414-A1 18-0844 for Yamaha 75 115 150 200 225 HP Outboard
Product Overview
Thermostat housing gasket for the Yamaha 75 to 225 HP two stroke outboards, the paper gasket that seals the thermostat cover to the housing. It replaces Yamaha 688-12414-A1 and the earlier 688-12414-00 and 688-12414-A0, it also crosses to Sierra 18-0844, and it ships as one gasket in a 150 mm x 180 mm x 10 mm pack at 11 g.
The gasket sits between the thermostat cover and the housing on top of the powerhead. It is a single use part: it compresses when the cover is torqued down and it usually tears when the cover comes off, so it is replaced whenever the thermostat is serviced.
A perished gasket shows up as a weep at the cover, a crust of dried salt around the joint, or a tell tale that spits. Left alone, the leak runs onto the powerhead and the cover bolts corrode into the housing, which turns a five minute job into a drilling job.
Fitting a new gasket at the same time as the thermostat is the sensible way to do the job. The cover has to come off either way, and reusing a compressed gasket is where repeat leaks come from.
Fitment covers the Yamaha 75A through 225D carburettor two strokes and the Z150 to Z200 HPDI models listed below, and the Honda thermostat numbers cross referenced in the table. Check the model code on the engine plate and the number on the old gasket before ordering.
Specifications
| Specification | Detail |
|---|---|
| Condition | New / New with tags |
| Type | Thermostat housing gasket |
| Yamaha Part Number | 688-12414-A1 |
| Supersedes | 688-12414-00, 688-12414-A0 |
| Sierra Number | 18-0844 |
| Application | Thermostat cover to housing joint |
| Fits | Yamaha 75 to 225 HP two stroke and HPDI outboards |
| Quantity | 1 gasket |
| Net Weight | 11 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 |
|---|---|
| Yamaha | 688-12414-A1 |
| Yamaha | 688-12414-00, 688-12414-A0 |
| Sierra | 18-0844 |
| Honda | 19300-ZW9-003, 19300-881-741, 19300-921-003 |
| Yamaha | 6AH-13411, 6E5-12411-00, 6E5-12411-01 |
| Yamaha | 6E5-12411-02, 66M-12411-00, 66M-12411-01 |
| Yamaha | 6G8-12411-00, 6G8-12411-01, 6G8-12411-02, 6G8-12411-03 |
Compatible Engines
| Yamaha Two Stroke Models |
|---|
| 75A, E75B, 75C, 80A, 85A |
| 90E, 90A, 100A, 115E, 115A |
| E115A, 115B, 115C, 130B, 140A |
| 140B, 150E, 150A, 150C, 150F |
| 150G, D150H, 150J, 150L, D150N |
| 175A, 175B, 175D, 175F, 200E |
| 200A, 200B, 200C Pro V 200, 200F, 200G |
| 200J, 220A, 225A, 225B, 225D |
Compatible HPDI Engines
| Yamaha Two Stroke HPDI Models |
|---|
| Z150P, Z150Q, Z175G, Z175H, Z200N, Z200P |
What's Included
| Component | Detail | Qty |
|---|---|---|
| Thermostat housing gasket | Replaces 688-12414-A1, 688-12414-00 and 688-12414-A0 | 1 |
| Thermostat | Not included, check it while the cover is off | 0 |
| Thermostat seal | Not included, inspect it before refitting the cover | 0 |
| Cover bolts | Not included, reuse the original fasteners | 0 |
Key Features
| Feature | Detail |
|---|---|
| Direct fit | Cut to the Yamaha thermostat housing and cover |
| Supersedes the old numbers | One gasket covers 688-12414-00 and 688-12414-A0 |
| Cross referenced | Also listed as Sierra 18-0844 |
| Single use part | Replace it every time the cover comes off |
| Wide coverage | 75A to 225D two strokes and the Z150 to Z200 HPDI |
| Small and light | 11 g, 150 mm x 180 mm x 10 mm pack |
Packing Dimensions
| Measure | Millimetres | Inches |
|---|---|---|
| Pack length | 150 mm | 5.91 in |
| Pack width | 180 mm | 7.09 in |
| Pack height | 10 mm | 0.39 in |
| Weight with packaging | 11 g | 0.39 oz |
Signs The Gasket Needs Replacing
| What You See | What It Means | Action |
|---|---|---|
| Weep at the thermostat cover | Gasket failed at the joint | Fit the new gasket |
| Dried salt crust around the cover | Slow leak evaporating | Fit the new gasket |
| Tell tale spitting or weak | Air drawn in at the cover | Fit the new gasket |
| Corroded cover bolts | Long term leak onto the bolts | Fit the new gasket and clean the threads |
| Thermostat serviced | Gasket is single use | Fit the new gasket on refit |
| Overheat after a repair | Old gasket not sealing the joint | Fit the new gasket and recheck the seal |
Fitting Notes
| Step | Action |
|---|---|
| 1 | Check the model code and the number on the old gasket |
| 2 | Let the engine cool and drain down to the thermostat level |
| 3 | Take the cover bolts out evenly and lift the cover |
| 4 | Scrape both faces clean without scoring the aluminium |
| 5 | Check the thermostat and its rubber seal while the cover is off |
| 6 | Fit the new gasket dry and squarely on the housing |
| 7 | Refit the cover and tighten the bolts evenly in a cross pattern |
| 8 | Run the engine on flush muffs and check the joint for leaks |
Condition & Warranty
| Item | Detail |
|---|---|
| Condition | New / New with tags |
| Warranty | 3 year |
| Packaging | Pack, 150 mm x 180 mm x 10 mm |
Before You Buy
- Replaces Yamaha 688-12414-A1
- Supersedes 688-12414-00 and 688-12414-A0
- Also crosses to Sierra 18-0844
- Fits the Yamaha 75A, 85A, 90A, 115B, 150A, 175B, 200A and 225B two strokes
- Fits the Z150P, Z175G and Z200N HPDI models
- One thermostat housing gasket, 11 g with packaging
- Pack 150 mm x 180 mm x 10 mm
- 30-Day Easy Returns
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