Mercury Quicksilver Flo-Torq II Hub Kit 835257K6 | Mercury & Mariner Outboards
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Mercury / Quicksilver OEM Flo-Torq II Propeller Hub Kit — Part No. 835257K6
| Part Number | 835257K6 |
|---|---|
| Brand | Mercury Marine / Quicksilver |
| Product Type | Flo-Torq II Slip-Clutch Propeller Hub Kit |
| System | Propulsion / Propeller Drive |
| Sold As | Complete kit (hub, insert, and hardware) |
| HS Code | 848790 |
About This Kit
The 835257K6 is a genuine Mercury Marine / Quicksilver OEM Flo-Torq II propeller hub kit for select Mercury and Mariner outboard engines. The Flo-Torq II system uses a slip-clutch design that allows the propeller to slip on the hub during a strike event, absorbing the impact shock before it can travel up the driveshaft and into the gearcase. This protects the gearcase, driveshaft, and engine from damage that would otherwise result from a sudden propeller stop.
The K6 suffix identifies a specific hub body and insert combination defined by propeller bore size and engine spline count. It is not interchangeable with other Flo-Torq II kit variants (K1, K2, K3, etc.) even if the propeller appears similar. Confirm the correct kit number using your engine model, serial number, and propeller part number before ordering.
Compatible Applications
Fitment is determined by engine model, serial number, and propeller bore/spline configuration. Verify the required hub kit using the Mercury propeller and hub application chart for your specific engine before ordering.
- Select Mercury outboard engines — confirm by serial number and propeller application chart
- Select Mariner outboard engines — confirm by serial number and propeller application chart
Do not order by engine horsepower alone — multiple Flo-Torq II variants cover overlapping HP ranges and the correct kit is determined by spline count and propeller bore, not HP.
Kit Contents
- 1 × Flo-Torq II hub body
- 1 × drive sleeve / insert (matched to engine spline and propeller bore)
- Required mounting hardware for complete installation
When to Replace
- After a propeller strike — inspect the hub insert for shear or deformation even if the propeller appears undamaged
- Propeller slipping under load at normal operating RPM (worn or fatigued insert)
- Loss of thrust or inability to reach normal WOT RPM without propeller damage
- Visible cracking, deformation, or rubber deterioration in the hub insert
- Installing a replacement propeller that requires the correct hub configuration
- Routine inspection reveals hub wear beyond service limits
Installation Notes
- Confirm the K6 is the correct kit for your engine and propeller — verify against the Mercury propeller/hub application guide using your engine serial number
- Inspect the driveshaft splines for wear or damage before installing the new hub
- Inspect the propeller bore for wear, corrosion, or deformation that would prevent proper hub seating
- Install the correct insert for your propeller bore and engine spline count — the kit supplies the matched insert
- Seat the hub assembly fully before fitting the propeller nut
- Torque the propeller nut to the specification in the Mercury outboard service manual for your engine
- Always use a cotter pin or locking device as specified to prevent the nut from backing off
Related Products
- Mercury Quicksilver Flo-Torq II Hub Kit 835257K1 — K1 variant for Mercury & Mariner outboards
- Mercury Quicksilver Flo-Torq II Hub Kit 835274Q1 — 150–300 HP 4-Stroke & VMAX SHO applications
- Mercury MerCruiser Flo-Torq SSR Hub 8M0101602 — SSR hub for MerCruiser sterndrive applications
- Mercury MerCruiser Flo-Torq SSR HD Hub 8M0101601 — SSR HD heavy-duty hub for high-performance applications
- Mercury Propeller Nut Kit 8M0056235 — OEM propeller nut kit
- Mercury MerCruiser Drive Sleeve 835290Q1 — drive sleeve for propeller hub systems
- Mercury MerCruiser Quicksilver Thrust Washer 835467Q01 — thrust washer used with propeller hub assemblies
Parts Desk Insights
The Flo-Torq II line has several kit variants and the most common mistake is ordering by horsepower rather than by the hub chart. The K6 is defined by a specific spline count and propeller bore combination — if you fit a K1 insert into a propeller that requires K6 geometry, the hub won’t seat correctly and the slip-clutch won’t perform as designed. After any propeller strike, always pull and inspect the hub insert — the rubber or plastic insert is the sacrificial component and it can look intact while still being fatigued internally. A hub that slips at normal cruise RPM is a clear sign the insert is worn out and needs replacement before the next run. If you’re unsure which Flo-Torq II variant you need, your engine serial number and propeller part number together will pinpoint the correct kit.
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.
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For return authorization, please contact our support team before shipping anything back.