PAIR 807166A3 Exhaust Water Shutter Kit for MerCruiser V6 V8 Offset Plate Y-Pipe Retrofit, Replaces 14348A1, 18-2732, 9-42802 (Set of 2)

This is an exhaust water shutter retrofit kit that replaces OEM 807166A3 (and the older 14348A1 single-plate shutter). It is designed for MerCruiser V6 & V8 engines with the older offset-plate / Center Rise Y-pipe (approximately 1982–1996), and some diesel D3.0/D3.6/D4.2 applications (1992–1995).

The kit includes a new dual-clapper shutter and an adapter ring that mounts on top of the old style Y-pipe — converting the failure-prone single-plate-and-shaft design to the reliable dual-clapper design. This is NOT a replacement for 807166A1 — the two fit different Y-pipes and are not interchangeable.

Ships as one pair (2 shutter kits) — covers both sides of the Y-pipe. For a single, see GHMarine 17ST004. V6/V8 Y-pipes typically use two shutters (one per side) — this pair covers both in one purchase.

Why this part matters — the old 14348A1 failure chain

The old style 14348A1 shutter was a single metal plate on a stainless shaft. Over years of use, the shaft wears through the plate hinge points. When it fails:

1. The plate drops into the Y-pipe and exits through the propeller (often unnoticed).

2. Or the loose shaft lodges at the bottom of the Y-pipe and vibrates a hole through the aluminum wall — causing water to enter the bilge when the engine is off.

The 807166A3 retrofit kit is Mercury's official fix: a new dual-clapper shutter with an adapter ring that fits the old Y-pipe. Replacing the old shutter before it fails is far cheaper than TIG-welding a hole in the Y-pipe or replacing the entire pipe (which requires engine removal).

Signs yours is due

·       Ticking or clacking noise from the Y-pipe area at idle — the old single-plate shutter (14348A1) has worn through its shaft and the metal pin is rattling inside the pipe.

·       Small hole in the Y-pipe — the old style shutter shaft wears through and drops to the bottom of the Y-pipe, vibrating a hole through the aluminum wall. Water enters the bilge when the engine is off.

·       Engine overheating event — heat melts the rubber shutter; fragments can lodge in the Y-pipe and block exhaust flow.

·       Found old shutter fragments or a loose metal shaft in the exhaust or lower unit — the old 14348A1 has failed. Inspect the Y-pipe interior for wear holes before installing the retrofit kit.

·       Routine transom service or manifold replacement — if you have an older offset-plate Y-pipe (1982–1996), upgrade to the 807166A3 retrofit kit before the old style shaft wears through the pipe.

Will it fit my drive?

This exhaust water shutter retrofit kit is Compatible with MerCruiser V6 & V8 engines with an offset-plate / Center Rise Y-pipe (approximately 1982–1996), and some diesel D3.0/D3.6/D4.2 applications (1992–1995, per Recmar). Engine horsepower alone does not prove fit — match your drive serial number, Y-pipe casting number, and grommet hole type (round = A3).

Brand	Model / Drive	Rated HP	Stroke	Years	OEM Part No.
MerCruiser	V6 & V8 · Center Rise & 4in Y-pipe · offset plate	120–425	4-Stroke	1982–1996	807166A3
MerCruiser	Diesel D3.0 / D3.6 / D4.2 · offset plate	per engine	Diesel	1992–1995	807166A3

 

OEM & swap numbers

Primary OEM is 807166A3 (2.50 in cross pin, round grommets, retrofit kit with adapter ring). Replaces the old 14348A1 single-plate shutter. Common interchange refs: Sierra 18-2732, Mallory 9-42802, PROmarine 65166P, Recmar REC807166A3.

Type	Brand	Part Number	Notes
OEM	Mercury / Quicksilver	807166A3	Primary OEM · 2.50 in cross pin · round grommets · retrofit kit with adapter ring
OEM (old)	Mercury	14348A1	Old single-plate + shaft style · superseded by 807166A3 kit
Aftermarket	Sierra	18-2732	1:1 direct replacement · catalog PKG OF 2
Aftermarket	Mallory	9-42802	1:1 direct replacement
Aftermarket	PROmarine	65166P	Center Rise · Qty 2 · 1982-1996
Aftermarket	Recmar	REC807166A3	Includes diesel D3.0/D3.6/D4.2L applications

 

Wrong part? Read before you order

·       NOT for new-style 4in Y-pipe with square grommets (1996+) — uses 807166A1 (2.48 in cross pin); see GHMarine 17ST002 / 17ST003.

·       NOT for 4.3L V6 one-piece manifold (batwing) — uses 807166A2 (2.98 in cross pin); see GHMarine 17ST007 / 17ST008.

·       NOT for 3 inch Y-pipe (1982–1987) — uses 99370A2; see GHMarine 17ST006.

·       NOT for 4-cyl / jackshaft engines — uses 60930; see GHMarine 17ST001.

·       NOT for use as a universal supersession for A1 — A3 and A1 fit different Y-pipes and are NOT interchangeable.

How to identify your correct shutter — check Y-pipe grommet holes

·       Round holes → you need 807166A3 (this part) — old offset-plate / Center Rise Y-pipe (1982-1996)

·       Rectangular holes → you need 807166A1 (different SKU 17ST002/003) — new-style 4in Y-pipe (1996+)

·       Y-pipe changes size below the shutter → one-piece V6 batwing manifold, you need 807166A2 (17ST007/008)

Cross pin diameters are NOT interchangeable: A1 = 2.48 in, A2 = 2.98 in, A3 = 2.50 in.

Y-pipe casting numbers (reference): 44266T1 = old offset (use A3); 807130A4 = new 2-piece (use A1); 807130A7 = V6 1-piece (use A2).

What ships in the box

·       2 × Exhaust water shutter retrofit kits (one pair) — each includes dual-clapper shutter + adapter ring + grommets. Covers both sides of the Y-pipe. For a single, see 17ST004.

·       Not included: hose clamps (reuse existing), tools, Y-pipe (sold separately if damaged)

Installation overview

The 807166A3 is a retrofit kit — it sits ON TOP of the old style Y-pipe, not inside it. No bellows adhesive or expander tool is needed (this is a water shutter, not a bellow).

1. Remove the exhaust elbow/riser to access the top of the Y-pipe.

2. Inspect the Y-pipe interior with a borescope or mirror — if the old 14348A1 shaft has worn a hole through the Y-pipe wall, that must be repaired (TIG weld or pipe replacement) before installing the retrofit kit.

3. Remove the old single-plate shutter and any shaft fragments from the Y-pipe.

4. Install the adapter ring onto the top of the Y-pipe (round grommet holes).

5. Mount the new dual-clapper shutter onto the ring with the cross pin seated in the round grommets.

6. Reinstall the exhaust elbow/riser. Run on muffs and check for exhaust leaks.

The A3 kit will look larger than the old shutter opening — this is normal. It is designed to sit on top of the pipe, not inside it. Most applications require removing the exhaust elbow for access, but NOT the engine.

Often replaced together

·       Exhaust bellow (bell housing) — GH SKU 17B1003 (ref 8M0124227 / 18654A1 family).

·       U-joint bellow — GH SKU 17B1004 (Gen I) or 17B1007 (Gen II).

·       Shift cable bellow — GH SKU 17B1005 (ref 74639A2).

·       Transom repair kit — GH SKU 17B3005 (Gen I) / 17B3007 (Gen II) / 18B5001 (Bravo).

FAQ

Will this fit my MerCruiser sterndrive?

This replaces OEM 807166A3 on MerCruiser V6 & V8 engines with an older offset-plate / Center Rise Y-pipe (approximately 1982–1996), and some diesel D3.0/D3.6/D4.2 applications (1992–1995). Check your Y-pipe grommet holes: round = A3 (this part), rectangular = A1 (different part 17ST002). Match your drive serial number and Y-pipe casting number before ordering.

Is this a pair or a single?

This listing is for a pair of shutter kits (2 pieces) — covers both sides of the Y-pipe. For a single, see GHMarine 17ST004. V6/V8 Y-pipes typically use two shutters (one per side) — this pair covers both in one purchase.

Why does this look too big for my Y-pipe?

The 807166A3 is a retrofit kit — it sits ON TOP of the old style Y-pipe, not inside it. The kit includes an adapter ring that mounts to the top of the Y-pipe and holds the new dual-clapper shutter. This is by design. If your shutter slides inside the pipe with no adapter ring, you likely need 807166A1 (17ST002) instead.

How do I know it needs replacing?

The old style 14348A1 single-plate shutter has a metal shaft that wears through over time. When it fails, the plate drops into the Y-pipe and the loose shaft rattles a hole through the aluminum wall — causing water to enter the bilge. If you hear clacking at idle, find shaft fragments, or see a small hole in the Y-pipe, replace with the 807166A3 retrofit kit.

Could this be the wrong part?

A3 (this part) has round grommet holes and a 2.50 in cross pin — for older offset-plate Y-pipes (1982–1996). A1 has rectangular grommets and 2.48 in cross pin — for new-style 4in Y-pipes (1996+). A2 has a 2.98 in cross pin — for 4.3L V6 one-piece batwing manifolds. The three are NOT interchangeable. Check grommet hole shape and cross pin diameter.

Do I need to check the Y-pipe too?

Yes. If the old 14348A1 shaft has already worn a hole through the Y-pipe wall, installing the A3 retrofit kit alone will not stop water intrusion. Inspect the Y-pipe interior with a borescope or mirror before reassembly. Small holes may be TIG-welded; larger damage requires replacing the Y-pipe.

I have a 4.3L V6 — is this the right part?

Many 4.3L V6 engines came with one-piece manifolds that were later converted to two-piece. But the Y-pipe was usually NOT changed (that requires engine removal). If your Y-pipe is the old offset-plate style with round grommet holes, you need A3 (this part). If it is the new-style with rectangular holes, you need A1 (17ST002). Check the Y-pipe casting number, not just the manifold type.

Please note

Aftermarket replacement part. Not affiliated with engine manufacturers named above. "Compatible with", "Replaces", and cross-ref numbers mean this part is built to work like the originals listed — always confirm fit with your drive serial number and Y-pipe grommet hole type before ordering.