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Yamaha F75-F115 Intake Valve Stem Seal Pro Marine A3721
Yamaha F75-F115 4-Strk 99-Up
Mercury 75-115hp 4-Strk
| Quantity | Price |
| 1 | 6.99 |
Pro Marine Aftermarket Intake Valve Stem Seal
Yamaha F75-F115 Intake Valve Stem Seal - Pro Marine A3721
The Pro Marine A3721 Intake Valve Stem Seal is an aftermarket replacement for select Yamaha four-stroke outboard cylinder heads using Yamaha OEM K0A-A3721-00-00.
Verified applications include select F75, F80, F90, F100, F115 and LF115 Yamaha four-stroke engines.
Pro Marine also stocks the genuine Yamaha OEM version, plus the matching exhaust valve seals, valve spring, intake valve and exhaust valve used during cylinder-head rebuilding.
Pro Marine: A3721
Yamaha OEM: K0A-A3721-00-00
Application: Intake Valve Stem Seal
OEM & Cross Reference Numbers
| Brand / Type | Part Number |
|---|---|
| Pro Marine | A3721 |
| Yamaha OEM | K0A-A3721-00-00 |
Yamaha Outboard Fitment
| Engine Family | Verified Applications |
|---|---|
| F75 |
F75TLRB - 2003 F75TLRC - 2004 F75TLRD - 2005 F75LA / F75LA_0112 - 2006-Present F75TLR / F75TLR_041 - 2006-Present |
| F80 |
F80TLRX / F80TXRX - 1999 F80TLRY / F80TXRY - 2000 F80TLRZ - 2001 F80TJRA / F80TLRA - 2002 F80TJRB / F80TLRB - 2003 |
| F90 |
F90TJRB / F90TLRB - 2003 F90TJRC / F90TLRC - 2004 F90TJRD / F90TLRD / F90TXRD - 2005 F90JA / F90JA_0112 - 2006-Present F90LA / F90LA_0112 - 2006-Present F90TJR / F90TJR_041 - 2006-Present F90TLR / F90TLR_041 - 2006-Present F90TXR / F90TXR_041 - 2006-Present F90XA / F90XA_0112 - 2006-Present |
| F100 |
F100TLRX / F100TXRX - 1999 F100TLRY / F100TXRY - 2000 F100TLRZ / F100TXRZ - 2001 F100TLRA / F100TXRA - 2002 F100TLRB / F100TXRB - 2003 |
| F115 - 2000-2005 |
F115TLRY / F115TXRY - 2000 F115TLRZ / F115TXRZ - 2001 F115TJRA / F115TLRA / F115TXRA - 2002 F115TJRB / F115TLRB / F115TXRB - 2003 F115TJRC / F115TLRC / F115TXRC - 2004 F115TJRD / F115TLRD / F115TXRD - 2005 |
| F115 - Later Models | F115JA, F115LA, F115TJR, F115TLR, F115TXR and F115XA applications from 2006-Present, including supplied 011, 061, 04 and 0405-0411 suffix variants. |
| LF115 |
LF115TXRY - 2000 LF115TXRZ - 2001 LF115TXRA - 2002 LF115TXRB - 2003 LF115TXRC - 2004 LF115TXRD - 2005 LF115TXR / LF115TXR_0 / 0405-0407 - 2006-Present LF115XA / LF115XA_01 / LF115XA_06 - 2006-Present |
Verify the complete Yamaha model number before ordering. Yamaha used different cylinder-head and valve-train components across similar horsepower families.
Confirm that the engine application calls for K0A-A3721-00-00.
Genuine Yamaha OEM Option
Yamaha OEM Intake Valve Stem Seal - K0A-A3721-00-00
Prefer genuine Yamaha? Pro Marine also stocks the OEM intake valve stem seal for the same compatible applications.
Brand: Yamaha OEM
OEM Number: K0A-A3721-00-00
Related Cylinder Head Rebuild Parts
Pro Marine Valve Spring - 67F-12114P
Replacement valve spring for compatible Yamaha F75-F115 four-stroke cylinder heads.
OEM: 67F-12114-00-00
View Valve Spring
Yamaha OEM Exhaust Valve Stem Seal
Genuine Yamaha OEM exhaust-side valve stem seal for compatible four-stroke cylinder heads.
Brand: Yamaha OEM
View OEM Exhaust Valve Seal
Pro Marine Exhaust Valve Stem Seal - A3722
Aftermarket exhaust valve stem seal for compatible Yamaha four-stroke engines.
Brand: Pro Marine
View Pro Marine Exhaust Seal
Pro Marine Intake Valve - 68V-12111P
Length: 96.9mm
Head Diameter: 29mm
Replacement intake valve for compatible Yamaha four-stroke cylinder-head rebuilds.
View Intake Valve
Pro Marine Exhaust Valve - 68V-12121P
Length: 99.3mm
Head Diameter: 23.9mm
Replacement exhaust valve for compatible Yamaha four-stroke cylinder-head rebuilds.
View Exhaust ValveValve Train Service Components
| Component | OEM / Aftermarket Option |
|---|---|
| Intake Valve Stem Seal | Pro Marine A3721 / Yamaha OEM K0A-A3721-00-00 |
| Exhaust Valve Stem Seal | Pro Marine A3722 / Yamaha OEM K0A-A3722 |
| Valve Spring | Pro Marine 67F-12114P |
| Intake Valve | Pro Marine 68V-12111P |
| Exhaust Valve | Pro Marine 68V-12121P |
What This Part is Used For
The intake valve stem seal fits around the intake valve stem and helps regulate the amount of engine oil that passes between the valve stem and valve guide.
The valve guide requires lubrication, but excessive oil entering past the guide can reach the intake port and combustion chamber. The valve stem seal helps control this oil flow while allowing the valve to move normally.
Why Intake Valve Stem Seals Matter
Valve stem seals operate in a high-temperature environment and can become hardened, worn or damaged over time. A deteriorated seal may allow excess oil into the combustion chamber.
During a cylinder-head rebuild, replacing valve stem seals while the valves are already removed can prevent having to disassemble the valve train again later.
When to Replace Valve Stem Seals
- During a complete cylinder-head rebuild
- When replacing intake or exhaust valves
- When servicing valve guides
- If seals are hardened, cracked, flattened or damaged
- When excessive oil usage is traced to the cylinder head
- After overheating or cylinder-head damage
- During a complete powerhead overhaul
Inspect These Components at the Same Time
- Intake valves
- Exhaust valves
- Exhaust valve stem seals
- Valve guides
- Valve seats
- Valve springs
- Spring retainers and keepers
- Camshaft lobes and journals
- Cylinder-head sealing surfaces
Shop Yamaha Engine Rebuild Parts by Model
Pro Marine stocks pistons, piston rings, main bearings, rod bearings, cylinder sleeves, valves, valve seals, gaskets and other internal Yamaha four-stroke engine components.
Shop Yamaha Engine Rebuild Parts by Model
Key Features
- Pro Marine aftermarket intake valve stem seal
- Pro Marine part number A3721
- Replaces Yamaha K0A-A3721-00-00
- Fits select Yamaha F75 four-stroke applications
- Fits select Yamaha F80 four-stroke applications
- Fits select Yamaha F90 four-stroke applications
- Fits select Yamaha F100 four-stroke applications
- Fits extensive Yamaha F115 applications
- Fits Yamaha LF115 applications
- Genuine Yamaha OEM intake seal available as an alternative
- OEM and Pro Marine exhaust valve seals linked above
- Valve spring linked above
- Pro Marine intake and exhaust valves linked above
FAQ
What Yamaha OEM number does Pro Marine A3721 replace?
A3721 replaces Yamaha K0A-A3721-00-00.
Is A3721 a Yamaha OEM part?
No. A3721 is the Pro Marine aftermarket version.
Can I buy the Yamaha OEM version instead?
Yes. The genuine Yamaha K0A-A3721-00-00 intake valve
stem seal is linked above.
Does A3721 fit Yamaha F115?
Yes. The supplied fitment includes extensive F115 applications from
early engines through later models.
Does this fit Yamaha F75, F80, F90 and F100?
Yes. Select models from each of those engine families are included
in the verified fitment above.
Does A3721 fit Yamaha LF115?
Yes. Multiple LF115 applications are included.
Do you stock the exhaust valve stem seal?
Yes. Both Yamaha OEM K0A-A3722 and
Pro Marine A3722 exhaust valve stem seals are linked above.
Do you stock the intake and exhaust valves?
Yes. Pro Marine 68V-12111P intake and
68V-12121P exhaust valves are linked above.
Do you stock the valve spring?
Yes. The Pro Marine 67F-12114P valve spring is linked above.
Dealer Discounts & Store Policies
Dealer / Marine Industry Discounts
Are you a marine dealer, technician, boat builder, or industry professional? We offer dealer pricing for qualified marine businesses.
Shipping Policy
- Free shipping on orders over $100 in the continental U.S.
- Orders received before 5:30 PM EST ship the same business day.
- Typical delivery time is 1-5 business days.
30-Day Return Policy
- Returns accepted within 30 days of delivery.
- Parts must be new, unused and in original packaging.
- Installed parts are not returnable.
- Return authorization is required before returning parts.
Need help verifying fitment?
Contact Pro Marine
Phone: 941-721-3000
Searchable Part Numbers & Terms
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