Mercury Marine OEM Screw M8 x 30 | 4000354 | 496 / 8.1L Oil Filter, Heat Exchanger, Power Steering & Outboard
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Mercury Marine OEM Screw M8 x 30 — Part 4000354
- Part Number: 4000354
- Full Catalog Number: 10-4000354
- Brand: Mercury Marine (Genuine OEM)
- Official Product Type: Hardware & Fasteners — Metric Screw
- Thread Size: M8 x 30 mm (approx. 1.18 in. length)
- Supersedes: 1993830 / 10-1993830 and 17022 / 10-17022 in applicable Mercury assemblies
- Application: Multi-application Mercury / MerCruiser fastener — match by OEM part number and diagram location
- Weight: approx. 0.02 kg
What It Is
The 4000354 is a genuine OEM M8 x 30 mm metric screw used across numerous Mercury, MerCruiser, and Mariner assemblies. Because Mercury uses this same fastener in several different systems, it should always be matched by OEM part number and the specific diagram location rather than by thread size and length alone — head design, finish, and thread specification can vary between similar-looking M8 screws from different assembly locations.
Compatible Applications
Match by OEM part number 4000354 and confirm against the parts diagram for your specific assembly. This is a multi-application fastener used across both MerCruiser sterndrive and Mercury outboard systems.
MerCruiser Sterndrive Applications
- MerCruiser 8.1L / 496 MAG — remote oil-filter assembly mounting
- Selected MerCruiser heat exchanger assemblies
- Selected MerCruiser power-steering pump and bracket assemblies
Mercury / Mariner Outboard Applications
- Clamp bracket and swivel bracket assemblies
- Selected gear-housing assemblies
- Selected trim-tab assemblies
- Various Mercury outboard assemblies where the diagram specifies 4000354
Not sure this is the correct screw? Send us your Mercury or MerCruiser serial number and tell us which assembly you are working on.
Part Numbers & Supersession
- 4000354 — Current Mercury Marine OEM reference
- 10-4000354 — Mercury fastener catalog format
- 1993830 / 10-1993830 — Earlier Mercury screw; superseded by 4000354
- 17022 / 10-17022 — Earlier Mercury screw; superseded by 4000354 in applicable assemblies
When to Replace
Replace this screw if it has:
- Damaged, stretched, or corroded threads
- A rounded or damaged head
- A bent or distorted shank
- Visible corrosion that compromises structural integrity
- Damage caused during removal
- Been designated for replacement in the applicable Mercury service procedure
For engine, steering, transom, or drive assemblies, use the specified OEM fastener rather than substituting generic hardware by thread size alone.
Service Interval
Inspect when the associated assembly is serviced or disassembled. Replace if threads or head show any damage. There is no fixed standalone replacement interval — replace on condition or whenever the service procedure specifies fastener replacement.
Installation Notes
- Confirm the diagram calls specifically for 4000354 at your assembly location before installing
- Verify the receiving threads are clean and undamaged before installation
- Keep this screw separated from similar M8 fasteners of different lengths during disassembly
- Use the torque specification and any thread treatment (e.g. thread-locking compound) specified for the exact assembly in the Mercury service manual
- Inspect any associated washer, lockwasher, or bracket while the fastener is removed — Mercury clamp-bracket diagrams commonly pair 4000354 with lockwasher 400257 in some applications
Technical FAQ
Q: Can I substitute a generic M8 x 30 screw for 4000354?
Not recommended for engine, steering, cooling, or drive assemblies. An M8 x 30 screw from another source may differ in head design, finish, plating, or thread specification from what the Mercury diagram requires. For non-structural applications you may have flexibility, but critical assembly points should use the OEM fastener to meet the original specification.
Q: What does 4000354 replace?
4000354 supersedes earlier Mercury numbers 1993830 (10-1993830) and 17022 (10-17022) in applicable assemblies. If your older parts list or diagram shows either of those numbers, 4000354 is the current OEM replacement.
Q: How do I know which assembly my screw belongs to?
Reference the Mercury parts diagram for your specific engine or drive assembly by model and serial number. 4000354 appears in multiple completely different systems — the diagram is the only reliable way to confirm you have the right fastener in the right location.
Q: Is 4000354 used on both outboards and sterndrives?
Yes. Verified applications include both MerCruiser sterndrive assemblies (496/8.1L oil filter, heat exchanger, power steering) and Mercury/Mariner outboard assemblies (clamp brackets, gear housings, trim tabs). Always match by diagram location, not by application type alone.
Parts Desk Insights
The most important thing to know about 4000354 is that Mercury uses the same M8 x 30 fastener across completely different systems — oil filter mounting, heat exchanger brackets, power steering, outboard clamp brackets, and more. That means a customer who measures an old screw and finds M8 x 30 could be ordering the right part or a wrong one from a different assembly location, depending on head style and finish requirements. Match by OEM number and diagram position, not by measurement alone. The other common issue is mixing this screw up with similar-length M8 fasteners from adjacent locations during a disassembly — if you are taking apart a MerCruiser accessory bracket or outboard clamp assembly, keep fasteners organized by location so they go back in the right spot.
Shipping information
In-stock and OEM parts: ship same or next business day.
Locally warehoused items: ship within 1-3 business days.
Special-order items: timeline confirmed after order.
Returns & warranty
Returns & Satisfaction Guarantee
We stand firmly behind the quality of every product we sell. Your confidence matters to us — and we back it with a straightforward 30-Day Satisfaction Guarantee.
If you are not fully satisfied, you may request a return within 30 days of delivery. All returns must receive pre-approval prior to being sent back. Unauthorized returns will not be accepted.
To qualify for a return:
Item must be in new, unused condition
Product must be in its original packaging
All parts, components, hardware, manuals, and accessories must be included
Packaging must be undamaged and suitable for resale
Important:
Electronics are strictly inspected. No returns on open-box electronics. Exceptions may apply only with prior written approval. Any electronic unit that has been installed, powered, activated, or altered may not be eligible for return.
We are serious about product integrity — and equally serious about taking care of our customers. If there is ever a product issue, contact us immediately so we can make it right.
For return authorization, please contact our support team before shipping anything back.