3863450 Lower Exhaust Hose with Bump 3.5×5.5-Inch · Fits OMC / Volvo Penta center-rise select, Replaces 18-2780-1, 89222, 3852741

3863450 Lower Exhaust Hose with Bump 3.5×5.5-Inch · Fits OMC / Volvo Penta center-rise select, Replaces 18-2780-1, 89222, 3852741

GHMarine lower exhaust hose with bump for select OMC / Volvo Penta center-rise packages — OEM 3863450, about 3.5-inch I.D. × 5.5-inch long with the molded bump in the middle. Cross-refs 18-2780 / 18-2780-1, 89222, 9-72800 / 9-72814, REC3863450. Legacy 3852741 only when your EPC supersession chain lists it.

This page sells one bump lower hose only. Need two bump lowers → GH 17B2003 (3863450 ×2). It is not the older no-bump lower 3852742 (GH 17B1012), not the upper 3852696 (GH 17B1011), and not a sterndrive seal bellow.

Which hose is this?

It is the later lower exhaust hose / coupler on center-rise packages that specify 3863450. The molded bump is part of the identity — if your old hose is smooth with no bump, you are on the wrong page.

It is not legacy no-bump lower 3852742 / 18-2781 (GH 17B1012), not upper 3852696 / 18-2779 (GH 17B1011), not drive / clutch-dog bellow 914036, not cone-clutch transom bellow 3850426 (GH 17B1010), and not the four-piece pack (GH 17B4001).

Signs yours is due

• Center-rise lower joint: the short hose with a clear middle bump (~3.5×5.5 in) is cracked, soft, or heat-glazed — stamped 3863450 / 18-2780-1 / 89222 when readable.
• Soot or cooling-water drip at the lower engine-bay exhaust joint (not a transom seal leak and not the upper short-hose position).
• Your old lower hose has the bump, but a chart pushed 3852742 / 18-2781 — stop: that is the earlier no-bump family.
• Divert: no bump → GH 17B1012. Upper short hose → GH 17B1011. Two bump lowers → GH 17B2003. Upper×2 + lower×2 → GH 17B4001.

Will it fit my drive?

This bump lower hose is Compatible with select OMC / Volvo Penta center-rise packages that specify 3863450 — representative bands include Ford 5.0 / 5.8L about 1991 & up and late center-rise / SX rows about 1994–1998. Original part number and bump shape decide fit — do not extend the year band past the EPC / dual-table rows without proof.

*Representative catalog bands. Final fit = OEM 3863450 + bump shape on the old lower hose / EPC — not horsepower alone.

OEM & swap numbers

Primary OEM 3863450. Cross-refs for this bump lower: 18-2780 / 18-2780-1, 89222, 9-72800 / 9-72814, REC3863450.

Wrong part? Read before you order

• NOT legacy no-bump lower 3852742 / 18-2781 (GH 17B1012)
• NOT upper short hose 3852696 / 18-2779 (GH 17B1011)
• NOT clutch-dog / drive bellow 914036
• NOT cone-clutch transom bellow 3850426 (GH 17B1010)
• NOT two-pack of this bump lower — that is GH 17B2003
• NOT four-piece upper+lower pack — that is GH 17B4001
• NOT a sterndrive seal / gimbal-bearing kit

What ships in the box

• 1 × Lower exhaust hose with bump (3863450 family · ~3.5×5.5 in)
• Clamps when supplied (photos often show 2 — confirm against package)

Often ordered with related SKUs

• Two bump lowers (3863450 ×2) → GH 17B2003
• Legacy no-bump lower → GH 17B1012
• Upper short hose → GH 17B1011
• Upper×2 + lower×2 pack → GH 17B4001

Install tips in the engine bay

Engine-bay center-rise lower-hose work. Cold engine; disconnect battery; follow the OMC / Volvo Penta exhaust procedure for your assembly. Confirm the old hose has the bump before you install 3863450. Usually you do not pull the sterndrive for this short lower coupler — do not copy a full transom-kit adhesive / expander recipe blindly.

1. Confirm old hose is bump lower 3863450 (~3.5×5.5 in) — not 3852742 and not upper 3852696.
2. Support the joint; loosen clamps; remove the old hose; clean mating tubes.
3. Seat the new hose fully with the bump oriented as on the old part; place clamps on the clamp lands if supplied.
4. Tighten to the service-manual specification for that assembly (no universal torque invented on this page).
5. Run and check for exhaust / water leaks at the lower joint before returning the boat to service.

FAQ

Does this hose have a bump?

Yes. 17B1013 is 3863450 with the molded bump. If your old hose has no bump, see GH 17B1012 (3852742).

Is 18-2779 / 89224 a replacement for this?

No. Those are upper-hose (3852696) crosses. This page uses 18-2780-1 / 89222 for the bump lower.

I need two bump lowers — is this the right SKU?

This box is qty 1. For two bump lowers, see GH 17B2003 (3863450 ×2).

Can I order from an open-ended year tag alone?

No. Do not order from an open-ended year tag. Confirm 3863450 + bump on the old hose or EPC (representative bands ~1991+ Ford / ~1994–1998 late center-rise).

What comes in the box?

One 3863450 bump lower hose and clamps when supplied (confirm against your package).

Do I pull the drive and use bellows adhesive?

Usually no for this short lower coupler. Follow the engine-bay hose method in your service manual — do not assume a pull-drive multi-boot kit procedure.

Please note

Aftermarket replacement by GHMarine. Not affiliated with engine manufacturers named above. "Compatible with", "Replaces", and cross-ref numbers identify the 3863450 bump lower family — always confirm bump shape, EPC, and package contents before ordering.