Upper Exhaust Bellows 70981A3 70981 18-2762 for MerCruiser 3.7L 5.0 5.7 V6 V8 15 Degree Riser 4 Inch Elbow — Germany Local Warehouse
Upper Exhaust Bellows 70981A3 70981 18-2762 for MerCruiser 3.7L 5.0 5.7 V6 V8 15 Degree Riser 4 Inch Elbow — Germany Local Warehouse
Product Overview
Upper exhaust bellows, an exhaust part for MerCruiser sterndrives running the 3 inch (76.2 mm) 15 degree centre mounted riser with a 4 inch (101.6 mm) elbow. It replaces 70981A3 and 70981 and crosses to Sierra 18-2762, and it ships as 1 x bellows with 2 x stainless clamps, 463 g with packaging. Shipped from our Germany local warehouse.
The bellows carries exhaust gas and cooling water from the riser down through the transom. Rubber that has sat through a German winter goes hard and cracks from the inside, so the split is usually there before anything looks wrong from outside.
This is the MerCruiser line built by Mercury Marine, and two numbers decide whether it is the right bellows: the riser angle, 15 degree centre mounted, and the elbow diameter, 4 inch. The straight riser takes a different part and it will not seal.
Specifications
| Specification | Detail |
|---|---|
| Condition | New / New with tags |
| Type | Upper exhaust bellows |
| Riser Fitment | 3 inch (76.2 mm) 15 degree centre mounted riser |
| Elbow Size | 4 inch (101.6 mm) |
| Material | Rubber with stainless clamps |
| Components | 1 x bellows, 2 x clamps |
| Shipping Weight | 463 g with packaging |
| Country of Origin | Taiwan |
OEM Cross Reference
| Brand | Part Numbers |
|---|---|
| MerCruiser | 70981A3 |
| MerCruiser | 70981 |
| Sierra | 18-2762 |
Compatible Engines
| Engine Family | Models | Displacement | Years |
|---|---|---|---|
| MerCruiser 4 cylinder | 165 HP, 170 HP, 180 HP, 190 HP, 3.7 L | 224 CID | 1980 to 1989 |
| MerCruiser 4 cylinder | 470, 485, 488 | 224 CID | 1980 to 1989 |
| Chevrolet small block V8 | 305, 5.0 L, 260 HP | 305 CID | 1983 and later |
| Chevrolet small block V8 | 350, 5.7 L, 260 HP | 350 CID | 1983 and later |
| Chevrolet small block V8 | 377 | 377 CID | 1983 and later |
| Chevrolet big block V8 | 454, 7.4 L | 454 CID | 1981 and later |
| Chevrolet big block V8 | 502, 8.2 L | 502 CID | 1981 and later |
| Chevrolet V6 | 229, 4.3 L | 229 CID | 1983 and later |
| Chevrolet V6 | 262, 4.3 L | 262 CID | 1983 and later |
What's Included
| Component | Detail | Qty |
|---|---|---|
| Upper exhaust bellows | 3 inch riser to 4 inch elbow, 70981A3 | 1 |
| Stainless steel clamp | Worm drive, riser end and elbow end | 2 |
Riser Angle and Elbow Size
| What To Measure | This Part | Wrong Part Looks Like |
|---|---|---|
| Riser mounting angle | 15 degree centre mounted | Straight or 30 degree riser, bellows will not seat |
| Riser outlet | 3 inch (76.2 mm) | 4 inch riser outlet, different bellows |
| Elbow diameter | 4 inch (101.6 mm) | 3 inch elbow from an earlier engine |
| Riser height above the transom | Standard MerCruiser height | Raised aftermarket riser, check clearance |
| Old part number on the bellows | 70981A3 or 70981 | Nothing legible, measure the joint instead |
| Number of clamps on the old joint | 2 | 1 clamp means someone reused the part once already |
Winter Lay-Up and Frost
| Situation | Effect on the Bellows | What To Do |
|---|---|---|
| Boat ashore October to April | Rubber hardens and takes a set, cracks on the first start | Renew before the season, not after |
| Water left in the exhaust side below -20 °C | Ice expands and splits the rubber at the ribs | Drain the exhaust side at lay up |
| Unheated hall or outdoor storage | Condensation runs down and sits in the bellows | Store with the drive down so it drains |
| Summer heat above 30 °C under a closed hatch | Rubber ages faster than on an open boat | Inspect the ribs each spring |
| Salt water from the Baltic or North Sea | Salt stays in the fabric between trips | Flush on muffs after every trip |
| Engine bay washed before storage | Water trapped against the elbow flange | Dry the bay before closing it up |
Exhaust Leak and the Engine Bay
| What You Notice | What It Means | What To Do |
|---|---|---|
| Exhaust smell in the bay at idle | Split bellows or a clamp off its seat | Stop and inspect before the next trip |
| Louder exhaust note than last year | Rubber has split under the ribs | Renew the bellows and both clamps |
| Headache after a slow run | Carbon monoxide reaching the cockpit | Ventilate, fix the leak, do not run the boat |
| Soot marks at the riser joint | Gas escaping past the clamp | Clean the flange and reseat with a new clamp |
| Exhaust flapper rattle | The shutter is loose in the same joint | Renew the flapper while the bellows is off |
| Water in the bilge after a run | Bellows split or the elbow gasket has failed | Check both joints, not just the bellows |
Fitting Notes
| Step | Action |
|---|---|
| 1 | Check the riser is 15 degree centre mounted with a 3 inch (76.2 mm) outlet |
| 2 | Measure the elbow at 4 inch (101.6 mm) before ordering |
| 3 | Clean the riser and elbow flanges of old rubber and scale, a new bellows will not seat on either |
| 4 | Renew the exhaust flapper and shutter while the joint is open, they fail at the same age |
| 5 | Seat both ends on the ribs in the groove before tightening a clamp |
| 6 | Tighten with the clamp screw clear of the flange, not on the flat of the rib |
| 7 | Run the engine on muffs and check the joint for exhaust smell before the first trip |
| 8 | Check the bay again after the first run, a leak here is a carbon monoxide risk |
Condition & Warranty
| Item | Detail |
|---|---|
| Condition | New / New with tags |
| Warranty | Standard |
| Packaging | Sealed retail packaging |
Shipping from Germany
| Destination | Warehouse | Note |
|---|---|---|
| Germany | Germany local warehouse | Domestic delivery, no import duty |
| Austria, Netherlands, Belgium | Germany local warehouse | EU delivery, no customs charge |
| Other EU destinations | Germany local warehouse | EU delivery, VAT included |
Before You Buy
- Check the riser is the 15 degree centre mounted type with a 3 inch (76.2 mm) outlet
- Measure the elbow at 4 inch (101.6 mm), the straight riser takes a different bellows
- Read 70981A3 or 70981 off the old bellows where it is still legible
- Renew the exhaust flapper and shutter while the joint is apart
- Clean the flanges back to bare metal and rubber free, or the new bellows will not seal
- This is the bellows and 2 clamps, the riser, elbow and flapper are not included
- 30-Day Easy Returns
- Ships from our Germany local warehouse
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