Upper Exhaust Bellows 70981A3 for MerCruiser 3.7L 5.0 5.7 V6 V8 Riser 18-2762
Upper Exhaust Bellows 70981A3 for MerCruiser 3.7L 5.0 5.7 V6 V8 Riser 18-2762
Product Overview
Upper exhaust bellows tube, a replacement exhaust part for MerCruiser sterndrives that run the 3 inch 15 degree centre mounted riser with a 4 inch elbow. It replaces 70981A3 and crosses to Sierra 18-2762, and it is supplied as 1 x bellows with 2 x stainless clamps.
The bellows carries exhaust and cooling water from the riser down through the transom. When it perishes, exhaust leaks into the engine bay, which on a petrol sterndrive is the one failure you cannot ignore: the engine bay fills with carbon monoxide and the boat smells of exhaust before it is even under load.
The 15 degree riser is the common MerCruiser fitment, used on the 3.7L four cylinder, the small block and big block V8s, and the V6 engines. Check the riser angle and the elbow diameter before ordering, because the straight riser uses a different bellows.
Specifications & Attributes
| Specification | Detail |
|---|---|
| Condition | New / New with tags |
| Type | Upper exhaust bellows tube |
| Riser Fitment | 3 inch 15 degree centre mounted riser |
| Elbow Size | 4 inch |
| Material | Rubber with stainless clamps |
| Components | 1 bellows, 2 clamps |
| Shipping Weight | 463 g with packaging |
OEM Cross Reference
| Brand | OEM Part Numbers |
|---|---|
| MerCruiser | 70981A3 |
| MerCruiser | 70981 |
| Sierra | 18-2762 |
Compatible Engines
| Engine Family | Models | Years |
|---|---|---|
| MerCruiser 4 cylinder | 165, 170, 3.7L, 180, 190, 470, 485, 488 manifolds | 1980-1989 |
| Chevrolet small block V8 | 305, 350, 377 | 1983 and later |
| Chevrolet big block V8 | 454, 502 | 1981 and later |
| Chevrolet V6 | 229, 262 | 1983 and later |
What's Included
| Component | Qty |
|---|---|
| Upper exhaust bellows | 1 |
| Stainless clamp | 2 |
Condition & Warranty
| Item | Detail |
|---|---|
| Condition | New / New with tags |
| Warranty | Standard |
| Packaging | Sealed retail packaging |
Before You Buy
- Check the riser is the 15 degree centre mounted type with a 3 inch outlet, the straight riser takes a different bellows
- Measure the elbow at 4 inch before ordering
- Replace the exhaust flapper and the shutter while the bellows is off, they are in the same joint
- Clean the riser and the elbow of old rubber and scale, or the new bellows will not seat
- Check for exhaust smell in the engine bay after the first run, a leak here is a carbon monoxide risk
- Inspect the bellows every season, they crack from the inside where you cannot see it
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