807166A2 Exhaust Water Shutter PAIR (Pack of 2) Stops Water From Backing Up Into the Motor Compatible with MerCruiser 4.3L V6

Pack of 2 exhaust water shutter kits — same OEM 807166A2 as GH 17ST007
(two complete kits). For MerCruiser 4.3L V6 GEN+ with
one-piece (batwing) manifold Y-pipe · cross pin ≈2.98". Helps stop seawater
backflow / hydrolock risk on reverse, steep launch, following seas, or hard throttle chop.
NOT 807166A1 / 807166A3 / 99370A2 / 60930.

Which shutter is this?

OEM 807166A2 · Quantity 2 complete kits (= two × 17ST007).
Same numbers as 32-08307. Photos may show one kit for clarity —
this listing ships two.

Signs yours needs replacement

·       Cracked, missing, or stiff rubber flapper — water can wash back on reverse or steep launch

·       Idle clatter that fades with throttle — often blamed on lifters or the drive first

·       Fragments in the Y-pipe bottom or drive exhaust passage (found when changing the water pump)

·       Hydrolock or “gulped water” scare after reverse, ramp launch, or hard throttle chop

·       Power feels choked — debris from a broken flapper can restrict exhaust

·       Converted from one-piece to two-piece manifolds but the old Y-pipe stayed — still this family

·       Old part stamped 807166A2 or cross-ref 32-08307 · measured pin ≈2.98"

Transom bellows leak? Different family (e.g. 17B1003).

Will it fit my engine?

“4.3” alone does not prove fit. Confirm one-piece manifold Y, old number 807166A2,
or pin ≈2.98". Verify serial. *Catalog years — confirm SN.

Brand	Model / Drive	Rated HP	Stroke	Years	OEM Part No.
MerCruiser	262 MAG (TBI) GEN+ one-piece	≈220	4-Stroke	1996–1999*	807166A2
MerCruiser	4.3LX / LXH / LH GEN+ · one-piece	≈175–190	4-Stroke	1996–1998*	807166A2
MerCruiser	4.3L EFI GEN+ TBI · one-piece	≈210	4-Stroke	1996–1999*	807166A2
MerCruiser	★ NOT — 4" Y two-piece A1 family	—	—	1996+*	807166A1
MerCruiser	★ NOT — offset / center-rise A3	—	—	1982–1995*	807166A3
MerCruiser	★ NOT — early 3" Y 99370A2	—	—	1982–1987*	99370A2

 

OEM & swap numbers

Replaces ref 807166A2 · cross-ref 32-08307 · catalog 710-807166A 2w.

Type	Part Number	Notes
OEM	807166A2	Primary · GEN+ one-piece · ≈2.98" pin · this SKU = qty 2
Cross-ref	32-08307	Replaces ref 807166A2 · network aftermarket
Catalog	710-807166A 2w	Land N Sea / MEC row · space variant of OEM

 

Wrong shutter? Read before you order

·       NOT a single kit — for one kit order GH 17ST007

·       NOT 807166A1 — two-piece / 4" Y (GH 17ST002 / 17ST003) · pin ≈2.48"

·       NOT 807166A3 — offset / old-pipe retrofit (GH 17ST004 / 17ST005)

·       NOT 99370A2 early 3" Y (GH 17ST006)

·       NOT 60930 tip family (GH 17ST001)

·       NOT a transom bellow — no bellows adhesive / expander

What's in the box

·       2 × Exhaust water shutter kits (807166A2 equivalent) — same part as GH 17ST007 × 2

·       Each kit typically includes the shutter plus 2 grommets — confirm photos / pack contents

·       Photos on this listing may show one kit; this SKU ships two complete kits

Related GHMarine SKUs

·       Need only one kit? → GH SKU 17ST007 (single)

·       Need two-piece / 4" Y shutter 807166A1? → GH SKU 17ST002 (single) / 17ST003 (pair)

·       Need offset retrofit 807166A3? → GH SKU 17ST004 / 17ST005

·       Need early 3" Y shutter 99370A2? → GH SKU 17ST006

Install tips

Same as single kit 17ST007. Y-pipe flapper job — not bellows adhesive.

1. Same install as single kit 17ST007. Confirm 807166A2 / pin ≈2.98" on one-piece manifold Y — not A1/A3.

2. You receive two complete kits — replace now + keep a spare, or do both sides if your layout uses two shutters.

3. If pieces are missing, dig the Y-pipe bottom and the drive exhaust passage before installing.

4. Do NOT use bellows adhesive or an expander.

FAQs — the bros want to know

Is this two of 17ST007?

Yes. Same OEM 807166A2. This listing is a pack of 2 complete kits. For one kit only, order GH 17ST007.

Is this the same as 807166A1?

No. 807166A2 fits the V6 one-piece (“batwing”) manifold Y-pipe (cross pin ≈2.98"). 807166A1 fits the two-piece exhaust Y-pipe (pin ≈2.48") — GH SKU 17ST002 / pair 17ST003.

I converted to two-piece manifolds — do I still need A2?

Often yes. Forum sticky advice: if the original one-piece Y-pipe was not swapped when manifolds were converted, you still need 807166A2. Confirm Y casting / old shutter / pin size.

Why buy a 2-pack?

Spare / dual-boat / replace while the path is open. Same fitment rules as the single kit.

Does “4.3” alone prove fit?

No. Same 4.3 can need A1, A2, A3, or even early 3" shutters. Match OEM number, Y-pipe, and ≈2.98" pin — serial ranges beat horsepower claims.

Do I need bellows adhesive?

No. That is for transom rubber bellows. This is a Y-pipe water shutter / flapper.

Please note

Aftermarket replacement part. Not OEM. Not affiliated with engine manufacturers referenced above. This SKU is a pack of 2 kits (same as two of GH 17ST007). "Compatible with", "Replaces ref", and cross-ref numbers identify fitment — always confirm with your serial number, one-piece vs two-piece exhaust path, cross-pin size (≈2.98"), and old part number before ordering.