Blackfish Cutlass Bearing 1x1-1/4x4 JON-BACK
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This 1" x 1-1/4" x 4" Blackfish cutlass bearing corresponds to the BACK size code used for Johnson Duramax naval brass sleeve bearings. Current references describe this bearing as a water-lubricated marine shaft bearing with a 1" shaft size, 1-1/4" outside diameter, and 4" overall length, built with a naval brass outer shell and a bonded nitrile rubber lining for dependable support in wet marine service.
Key Features
- Size code BACK with 1" ID x 1-1/4" OD x 4" length.
- Water-lubricated naval brass sleeve bearing design.
- Oil- and chemical-resistant nitrile rubber bonded to the shell.
- Adaptable for strut and stern tube mounts and also commonly used as rudder-stock and pintle bushings.
- Current listing data shows approximate metal wall thickness of 3/64" and gross weight around 0.4 lb.
Engine Compatibility
This is not an engine-specific part. It is a shaft bearing selected by shaft diameter, outside diameter, and bearing length for marine shaft-support applications such as struts, stern tubes, rudder stock, and pintle bushing use. The correct match is based on bearing dimensions and housing style rather than engine make alone.
Serial Number Fitment Notice
Match this bearing by shaft size, outside diameter, overall length, and housing application before ordering. For a part like JON-BACK / BACK, dimensional matching matters more than appearance, especially when multiple cutless bearings can look similar while carrying different clearances or shell thicknesses.
When This Part Needs Replacement
Replace the cutless bearing when the shaft feels loose in the bearing, when wear has substantially reduced the water grooves, or when vibration, noise, or uneven shaft support points to bearing wear. Duramax replacement guidance referenced by current marine distributors notes that replacement is commonly warranted once significant groove wear is present.
Installation Notes
Sleeve bearings like this are typically installed with a light press fit and then secured in place with cone-pointed set screws where the installation calls for them. Current installation guidance also notes that if shrink fitting is required, gradual cooling is preferred and impact loading on a chilled bearing should be avoided to protect the rubber-to-shell bond.
Alternate/Superseded Part Numbers
Current references support BACK as the manufacturer size code for this bearing. Related catalog references also show 870252100 as the corresponding Duramax / Johnson ordering number for this same 1" x 1-1/4" x 4" brass cutless bearing size.
Parts Desk Insight
The easy mistake with cutless bearings is ordering by the product name alone. For this one, the right match is 1" shaft x 1-1/4" OD x 4" length, because even a small dimensional mismatch can turn a simple bearing swap into an installation problem.
Shipping: Ships same or next day for fast Canada wide shipping. ⚓
Shipping information
In-stock and OEM parts: ship same or next business day.
Locally warehoused items: ship within 3–4 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.