Exhaust Bellows 3850426 18-1074 for Volvo Penta SX DP OMC Cobra Sterndrive
Exhaust Bellows 3850426 18-1074 for Volvo Penta SX DP OMC Cobra Sterndrive
Product Overview
Exhaust bellows for the Volvo Penta SX, DP and OMC Cobra sterndrives, supplied as 1 x exhaust bellows and 1 x stainless clamp. The bellows replaces 3850426 and 767724, it crosses to Sierra 18-1074 and Mallory 9-72711, it fits the Volvo SX, DP and Cobra from 1986 to 2001 and the OMC 3.0 L to 7.4 L engines listed below, and one kit ships at 489 g with packaging.
This is the exhaust bellows rather than the u-joint bellows. It carries the exhaust gas from the engine down through the transom and out through the drive, and it is the one that sits behind the u-joint bellows rather than around the joint.
It fails in the same way as any bellows, from the flexing. The rubber cracks at the folds, and once it is split the exhaust finds its way into the engine bay and the noise changes before anything else goes wrong.
The clamp is in the kit because the old one is destroyed coming off. A stainless clamp is supplied rather than a painted one because it lives in the exhaust flow and in salt water.
The same bellows is listed two ways, because the OMC Cobra was built by Volvo Penta and shares the number. One set of listings describes it by the Volvo SX and DP drives from 1986 to 2001, and the other describes it by the OMC engine sizes from 3.0 L to 7.4 L. Both are this part number, and both are covered below.
Specifications & Attributes
| Specification | Detail |
|---|---|
| Condition | New / New with tags |
| Type | Exhaust bellows |
| Part Numbers | 3850426, 767724 |
| Also Recorded As | 0767724 |
| Sierra Number | 18-1074 |
| Mallory Number | 9-72711 |
| Fits | Volvo Penta SX and DP sterndrives, OMC Cobra sterndrives |
| Volvo And Cobra Years | 1986 to 2001 |
| OMC Engine Sizes | 3.0 L, 4.3 L, 5.0 L, 5.7 L, 5.8 L and 7.4 L |
| Position | Transom exhaust, behind the u-joint bellows |
| Parts In Kit | 2 pieces |
| Quantity | 1 exhaust bellows and 1 stainless clamp |
| Net Weight | 489 g including packaging |
| Packaging | Pack |
| Warranty | 3 year |
OEM Cross Reference
| Component | Numbers |
|---|---|
| Exhaust bellows | 3850426, 767724, 0767724 |
| Sierra | 18-1074 |
| Mallory | 9-72711 |
Compatible Engines
| Platform | Drive | Years |
|---|---|---|
| Volvo Penta SX | SX sterndrive | 1986 to 2001 |
| Volvo Penta DP | DP sterndrive | 1986 to 2001 |
| OMC Cobra | Cobra sterndrive | 1986 to 2001 |
The OMC Cobra listings give the fitment by engine size rather than by drive, so both are set out here. These are the OMC applications:
| Engine | Model Code | Years |
|---|---|---|
| 3.0 L inline | 302 | Not stated on the listings |
| 4.3 L V6 | 43, 432, 434 | Not stated on the listings |
| 5.0 L V8 | 50, 502 | Not stated on the listings |
| 5.7 L V8 | 57, 572 | Not stated on the listings |
| 5.8 L V8 | 58, 584 | Not stated on the listings |
| 7.4 L V8 | 74, 744 | Not stated on the listings |
The Volvo Penta SX, DP and OMC Cobra drives share this bellows because the Cobra transom was built to the same pattern. The Volvo listings give 1986 to 2001 for the drives, and the OMC listings give the engine sizes without a year range. Match by the number on the old bellows, or send us the drive model and year and we will confirm before you order.
What's Included
| Component | Detail | Qty |
|---|---|---|
| Exhaust bellows | Replaces 3850426 and 767724, transom exhaust | 1 |
| Stainless clamp | Clamps the bellows to the transom housing | 1 |
| U-joint bellows | Not included, that is a separate bellows | 0 |
Key Features
| Feature | Detail |
|---|---|
| Exhaust bellows | The transom exhaust bellows, not the u-joint bellows |
| Direct replacement | Fits in place of 3850426 and 767724 |
| Cross referenced | Sierra 18-1074 and Mallory 9-72711 |
| Volvo and OMC | Covers the SX and DP drives and the OMC Cobra 3.0 L to 7.4 L |
| 1986 to 2001 | The year range given for the Volvo SX, DP and Cobra drives |
| Stainless clamp included | A painted clamp does not last in the exhaust flow |
Signs The Bellows Has Failed
| What You See | What It Means | Action |
|---|---|---|
| Exhaust noise under the engine cover | Bellows split, gas escaping inside the boat | Fit the bellows before the boat is used again |
| Cracks at the folds on inspection | Age, not a split yet | Fit the bellows at the next service |
| Exhaust smell in the engine bay | Gas leaking at the transom | Fit the bellows |
| Water in the bilge with the u-joint bellows intact | Exhaust bellows split | Fit the bellows |
| Clamp corroded through | Bellows held by nothing | Fit the bellows, the clamp is supplied |
| Black soot around the transom plate | Long term leak at the bellows | Fit the bellows and check the plate |
Fitting Notes
| Step | Action |
|---|---|
| 1 | Check the drive or engine against the tables above |
| 2 | Take the drive off and support it, the bellows is at the transom |
| 3 | Take the old clamp off and cut the old bellows away rather than prising it |
| 4 | Clean the transom housing and the drive end back to bare metal |
| 5 | Check the u-joint bellows while the drive is off, the two are replaced together |
| 6 | Fit the new bellows, seating the lip fully on both faces |
| 7 | Fit the stainless clamp and tighten it evenly around the housing |
| 8 | Check the bellows is not twisted, then run the engine and check for exhaust noise |
Condition & Warranty
| Item | Detail |
|---|---|
| Condition | New / New with tags |
| Warranty | 3 year |
| Packaging | Pack |
Before You Buy
- Exhaust bellows with stainless clamp for Volvo Penta and OMC sterndrives
- Replaces 3850426 and 767724
- Also recorded as 0767724
- Crosses to Sierra 18-1074 and Mallory 9-72711
- Fits the Volvo Penta SX and DP drives from 1986 to 2001
- Fits the OMC Cobra from 1986 to 2001
- Fits the OMC 3.0 L, 4.3 L, 5.0 L, 5.7 L, 5.8 L and 7.4 L engines
- This is the exhaust bellows, not the u-joint bellows
- 489 g with packaging
- 30-Day Easy Returns
- Free Worldwide Shipping
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