Mercury Propeller Wrench 15/16" 859046M3 – OEM Service Tool
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Mercury Propeller Wrench 15/16" – 859046M3
Part Number: 859046M3 (Mercury catalog prefix: 91-859046M3)
Brand: Mercury Marine (Quicksilver OEM)
Official Product Type: Propeller Wrench / Service Tool
Drive Size: 15/16"
System: Propeller Removal & Installation
Condition: New OEM
What It Does
The Mercury 859046M3 is a genuine OEM service tool — a 15/16" propeller wrench purpose-built for removing and installing propeller nuts on selected Mercury outboard and MerCruiser sterndrive applications. The 91- prefix in Mercury’s catalog system designates this as a service tool, not a replacement part. This is the larger-nut companion to the 13/16" wrench (859046M2) — used on applications where the propeller nut takes a 15/16" drive rather than 13/16".
Compatible Applications
- Selected Mercury outboard engines requiring a 15/16" propeller nut wrench — verify by model and service manual
- Selected MerCruiser sterndrive applications with 15/16" propeller nuts — verify by model and service manual
Note: This is a service tool, not an engine-specific replacement part. Compatibility is determined by the propeller nut size on your engine. Confirm the correct wrench size for your application in the Mercury service manual or parts diagram before ordering. If your engine uses a 13/16" propeller nut, see the 859046M2 (13/16" wrench) instead.
Dimensions
Wrench Size: 15/16" (fits 15/16" propeller nut flats)
Part Revision: M3 suffix indicates current production revision
Supersedes / Alternate Part Numbers
- 859046M3 — current Mercury OEM part number
- 91-859046M3 — full catalog format with service tool prefix
Kit Contents
Single OEM propeller wrench. No additional components included.
Service Interval
This is a service tool — no replacement interval applies. Replace if the wrench is cracked, the drive is worn, or the socket no longer seats squarely on the nut flats. A worn or ill-fitting wrench can round the nut flats, making future propeller removal significantly more difficult.
Technical FAQ
Q: How do I know if I need the 15/16" wrench or the 13/16" wrench?
Check the propeller nut on your engine with a standard wrench or socket set before ordering. The 15/16" wrench (this tool) fits larger propeller nuts found on higher-horsepower Mercury outboards and some MerCruiser sterndrive applications. The 13/16" version (859046M2) fits smaller nuts common on mid-range outboards. Your Mercury service manual will specify the correct nut size and torque value.
Q: Can I use a standard 15/16" socket instead of this OEM wrench?
In many cases a standard 15/16" socket will work. The OEM wrench is designed for the specific depth and clearance profile of Mercury propeller nuts, which can matter when hub or thrust washer geometry limits access. For regular service work, the OEM tool is the reliable choice.
Q: Should I use an impact wrench for propeller nut removal or installation?
Mercury service manuals specify hand-torque with a torque wrench for propeller nut installation. Impact wrenches risk over-torquing the nut or damaging propeller shaft threads. For removal only, a brief impact is sometimes used in the field, but installation must always be done to the specified torque value by hand.
Related Products
- Mercury Propeller Wrench 13/16" 859046M2 – OEM Service Tool
- Mercury Propeller Shaft Nut 858869 – 7/8"-14 UNF OEM
- Mercury Propeller Nut Kit 8M0056235
- Mercury MerCruiser Quicksilver Propeller Nut Kit 69578Q1
- Mercury Quicksilver Propeller Nut Kit 11-52707Q1
- Mercury Quicksilver Flo-Torq II Hub Kit 835257K6
Parts Desk Insights
Best Use Case: This wrench is the right choice for shops and serious DIY owners who regularly service larger Mercury outboards or MerCruiser drives and want the correct OEM tool for the job. It pairs well with a torque wrench for proper propeller installation and is especially useful when working in tight engine compartments where a standard socket and extension won’t seat cleanly on the nut.
Common Issues: Customers sometimes order the wrong size — the 13/16" and 15/16" wrenches look nearly identical and the size difference is easy to miss. Always measure your propeller nut or confirm the size in your service manual before ordering. The other common issue is using any wrench — OEM or otherwise — with an impact driver for installation. This is the fastest way to strip propeller shaft threads, which turns a simple prop swap into a major repair.
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.