32-44348T 4″ Wet Exhaust Pair Kit for MerCruiser Upper Exhaust Tube

GHMarine ships two matching 4-inch upper exhaust tubes in one carton — the wet-exhaust rubber that bridges the exhaust pipe to the inner transom plate inside each engine bay. Parts books label it an upper tube; yard slang often says upper bellow — same piece, two of them.

Built for twin-engine boats: port and starboard each take one tube when both sides use the 32-44348T upper. Running a single sterndrive? Skip this SKU — use GHMarine 17B1002 (one tube). Clamps ship when shown in photos; no bellows glue, no expander, no drive removal.

Port, starboard, or the wrong SKU?

This 2-pack is only the in-hull 4″ upper on the inner transom plate — not the big boot outside the transom (8M0124227 → 17B1003), not the riser bellow upstream (32-14358T → 17B1001 single or 17B2001 lower pair), and not the 3″ lower leg (32-90949T → 24B1052).

Before checkout: read the stamp on each removed rubber, measure both ends (4″×4″ here), and count how many engines you are fixing. Quantity in the carton does not change the install location — it matches engine count.

When to replace one side vs both uppers

·       Port vs starboard not matching: one engine sounds rough under the hatch while the other is quiet — often the louder side has a cracked 4″ upper at the inner transom plate. If hours and rubber age are the same, plan on both.

·       Bilge pump runs harder after a twin run — each upper carries water-mixed exhaust in-hull. A split on either engine dumps coolant into the bilge; do not assume the "dry" side is fine until you inspect both stubs.

·       Exhaust odor with both hatches open — leaking uppers can push CO into the compartment. On twins, check port and starboard before the next trip — not just the side that "looked bad."

·       Why order two when only one looks torn? Matching-age twins usually fail together; this kit avoids a second freight charge when the other upper goes soft two weeks later.

·       Overheat on either engine (impeller, raw-water blockage) — heat glazes both rubbers in the same season. Replace the uppers on every drive you ran hot.

·       Spring opener: soot weeping at the clamp lines, stiff or shiny rubber, corroded band screws — budget two uppers if both bays show age. Wetness outside the transom plate often means U-joint or bell boot (17B1003), not this in-hull tube.

Drive serial check — each engine counts

Horsepower ratings do not pick the tube — serial + stamp + diagram row do. On twins, repeat the check on port and starboard; this kit assumes both bays need the same 4″ upper.

Application	Years	Serial / check point	OEM ref	Notes
MerCruiser Alpha One Gen I / II	1983–present	Gen I: S/N 06225577 thru 0D469858; Gen II: 0D469859 and up	32-44348T	Twin Merc: verify each drive tag separately — kit = one upper per engine bay
MerCruiser Bravo One / Two	1988–present	Bravo SN 0B664190 and up family	32-44348T	Bravo twin installs use the same 4″ upper at the inner transom plate
MerCruiser MCM 4.3 / 5.0 / 5.7 / 6.2 / 7.4L V6/V8	1983–present	Match removed stamp + serial on every engine you are refreshing	32-44348T	Never stack two tubes on one exhaust run — qty 2 means two engines or spare pair
MerCruiser Blackhawk	1996–present	High-performance segment; confirm serial on both drives if twin	32-44348T	Same 4″×4″ upper family as Alpha / Bravo twin setups

 

Stamps & swap numbers (both tubes use the same family)

Factory current ID is 32-44348T; you may also see 32-44348001 or legacy 32-44348 molded on either engine. Swap lines commonly quoted: 18-2748, 89120, 9-72805, 9-72807.

Type	Part Number	Notes
OEM	32-44348T	Primary stamp — each tube in the kit matches this 4″×4″ upper
OEM	32-44348001	Factory catalog variant — same rubber as 32-44348T
OEM	32-44348	Pre-T suffix numbering — interchangeable upper tube
OEM ref	0775485	Older catalog line item for the same upper hose
Cross-ref	18-2748	Swap number — functionally replaces 32-44348T
Cross-ref	89120	Swap number — functionally replaces 32-44348T
Cross-ref	9-72805	Swap number — functionally replaces 32-44348T
Cross-ref	9-72807	Alternate tube listing tied to 32-44348T family
Cross-ref	REC32-44348001	Kit-style catalog ID for the upper tube line

 

Checkout guard — diameter, location, and carton count

The exhaust rubber family stacks four neighbours in one area. A twin order fails when any leg is wrong — verify all three:

·       One engine, one bad upper — choose GHMarine 17B1002 (qty 1). This listing is a two-tube carton.

·       Lower riser boots (32-14358T ×2) live upstream — GHMarine 17B2001 lower pair, not this upper pair.

·       Transom bell-housing wet boot 8M0124227 / 18654A1 — GHMarine 17B1003; drive-off, adhesive job.

·       Single lower riser bellow 32-14358T at the manifold elbow — GHMarine 17B1001, different leg of the path.

·       3″ lower exhaust leg 32-90949T — GHMarine 24B1052; smaller pipe and different location.

·       3″ or 3″-to-4″ upper 70981A3 — GHMarine 17B1014; measure your removed tube before checkout.

Two-tube kit — what is in the carton

·       2 × 4″ upper exhaust tubes (32-44348T family — one per engine bay)

·       Hose clamps when shown in product photos

·       Not shipped: bellows adhesive, expander tool, 17B2001 lower pair, 17B1003 bell boot, 17B1001 riser single, U-joint or shift bellows

Twin exhaust service — frequent add-ons

·       Lower pair at the riser — GHMarine 17B2001 (32-14358T ×2) when both manifold boots are due on a twin refresh.

·       One spare upper only — GHMarine 17B1002 if a single tube failed and the mate still looks good.

·       Transom bell boot (each drive) — GHMarine 17B1003 (8M0124227 family) — separate SKU, drive-off adhesive work.

·       3″ exhaust path — GHMarine 24B1052 (32-90949T) when either drive runs the smaller lower leg.

·       Opening both hatches once? Many twin owners renew clamps and all wet-exhaust rubbers in the same weekend.

Twin-bay install — clamp-on upper (repeat per engine)

Service manual path: engine stays in the boat; sterndrive stays on. The exhaust elbow may need to come off for hand room. Cold exhaust only. Do port, then starboard — same steps, second tube from the kit.

Tools & prep

·       Band clamps (included when shown) · driver for clamp screws

·       Wire brush / emery cloth for stub cleanup on both bays

·       Soapy water in a spray bottle — slides stiff 4″ rubber; keep oil off the exhaust joints

Per-engine sequence

1. Back off existing clamps; free the old upper from the exhaust stub and the intermediate / lower pipe. Slice the rubber if it is bonded to rust.

2. Pull the intermediate pipe when the manual calls for it; inspect the metal landing surfaces on that side.

3. Brush stubs bright, wipe dry, mist with soapy water. Warm stiff replacements in hot tap water if needed.

4. Slide clamps onto the new tube first, seat the rubber fully on both stubs, then tighten so each band bites the elbow, upper, and lower pipe evenly.

5. Idle test on muffs or in the water; listen for tick or hiss at both joints. Snug clamps again after the first hot run.

Second engine = repeat with tube #2. Transom bell work (17B1003) is a different job — adhesive and expander 91-45497A1 stay on that SKU, not this in-hull clamp tube.

FAQ — twin qty & fit

I only run one sterndrive — is the 2-pack wrong for me?

Yes — one engine needs one upper. Buy GHMarine 17B1002 (single tube). This SKU is for twin-engine boats refreshing port and starboard, or keeping a matched spare pair.

Twin Merc: one tube per engine, or both on one exhaust?

One per engine bay — never double-stack on a single exhaust path. Same 32-44348T stamp on port and starboard is normal; the kit is qty 2 for qty 2 engines.

Same rubber as your 17B1002 page?

Same molded 4″×4″ upper at the inner transom plate — only carton count changes. 17B1002 = 1 tube; 17B2002 = 2 tubes.

How do I rule out the 3 inch tubes before I buy?

Measure the piece you removed: both ends should read 4″ and sit engine-side of the inner transom plate. 3″ paths point to 70981A3 (17B1014) or 32-90949T lower (24B1052).

Molded number shows 32-44348001 or plain 32-44348 — still this kit?

Yes — three factory number generations, one upper tube design. Swap refs 18-2748, 89120, and 9-72805 also track back to this 4″ upper family.

Glue, expander tool, or pull the drive like the transom bellow?

No — in-hull clamp job. Exhaust must be cold; elbow may need to come off for reach. Repeat on the second engine bay for twins. Adhesive / 91-45497A1 is for 17B1003 territory.

Carton contents?

Two upper exhaust tubes (32-44348T family) plus hose clamps when shown in photos. No lower pair (17B2001), bell boot (17B1003), riser single (17B1001), or U-joint rubbers.

Please note

Aftermarket replacement — not made or sponsored by engine OEMs cited above. "Compatible with", "Replaces", and interchange numbers describe functional fit only. Confirm both drive or transom serials on twin installs before launching.