Sierra 18-2750 Exhaust Bellows, Replaces Mercury Marine 18654A1 32734A3, Fits Mercruiser Alpha One Gen II, Bravo I/II/III, Blackhawk

The Sierra 18-2750 Exhaust Bellows is a round, clamp-on replacement bellows for Mercruiser sterndrive exhaust systems. It is used to seal the exhaust passage between the drive unit and the transom on applicable Mercruiser drives, and a mounting clamp is included so the bellows can be installed as a complete unit. The bellows measures 5.2 inches L x 3.8 inches W and weighs 0.44 pounds.

This part fits Mercruiser Alpha One Gen II drives from 1991 and newer (serial number 0D469859 and up), Mercruiser Bravo I/II/III drives from 1988 and newer (serial number 0B664190 and up), and Mercruiser Blackhawk drives from 1994-1995 (serial number 0F18677 and up). It is a direct equivalent for Mercury Marine part number 18654A1 and part number 32734A3, so it can be ordered as a like-for-like replacement using either of those reference numbers. As with other exhaust bellows, this component is a wear item that should be inspected periodically and replaced if it shows cracking, hardening, or splitting, since a failed exhaust bellows can allow water intrusion into the boat.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-2750
• Category: Mercruiser Bellows
• Product Dimensions: 5.2 inches L x 3.8 inches W
• Weight: 0.44 pounds
• Shape: Round
• Installation Type: Clamp-On
• Included Components: Exhaust Bellows, Clamp
• OEM Equivalent Part Number: 32734A3, MERCURY MARINE 18654A1

Fitment

• Mercruiser Alpha One Gen II, 1991 and Newer, S/N 0D469859 and Up
• Mercruiser Bravo I/II/III, 1988 and Newer, S/N 0B664190 and Up
• Mercruiser Blackhawk, 1994-1995, S/N 0F18677 and Up

Replaces (OEM)

• Mercury Marine 18654A1
• 32734A3

Frequently Asked Questions

What does the Sierra 18-2750 exhaust bellows fit? The 18-2750 fits Mercruiser Alpha One Gen II drives from 1991 and newer (S/N 0D469859 and up), Mercruiser Bravo I/II/III drives from 1988 and newer (S/N 0B664190 and up), and Mercruiser Blackhawk drives from 1994-1995 (S/N 0F18677 and up).

Is the 18-2750 a direct replacement for Mercury Marine 18654A1? Yes, part number 18-2750 is a direct equivalent for Mercury Marine 18654A1 and can be ordered in its place.

Does 18-2750 cross-reference to 32734A3? Yes, 32734A3 is listed as an OEM equivalent number for the Sierra 18-2750 exhaust bellows.

What are the dimensions of the 18-2750 exhaust bellows? This bellows measures 5.2 inches in length by 3.8 inches in width.

How much does the 18-2750 exhaust bellows weigh? The 18-2750 weighs 0.44 pounds.

Does the 18-2750 come with a clamp? Yes, the Sierra 18-2750 exhaust bellows package includes a mounting clamp along with the bellows itself.

What shape is the 18-2750 exhaust bellows? The 18-2750 is a round exhaust bellows with a clamp-on installation design.

Will the 18-2750 fit an Alpha One Gen I drive? No, the 18-2750 is specified for Alpha One Gen II drives (1991 and newer, S/N 0D469859 and up), not the earlier Gen I generation.

Does 18-2750 fit Mercruiser Bravo III drives? Yes, 18-2750 is listed for Bravo I/II/III drives, 1988 and newer, S/N 0B664190 and up.

What years of Blackhawk drives use the 18-2750 bellows? The 18-2750 fits Mercruiser Blackhawk drives built in 1994-1995, S/N 0F18677 and up.

Why would I need to replace an exhaust bellows like the 18-2750? An exhaust bellows seals the exhaust path on the sterndrive, and the 18-2750 should be replaced if the bellows shows cracking, hardening, or splitting to prevent water intrusion.

How is the 18-2750 exhaust bellows installed? The 18-2750 is a clamp-on bellows, using the included clamp to secure it in place on the applicable Mercruiser Alpha One Gen II, Bravo I/II/III, or Blackhawk drive.