Sierra 47-237800 Oil Filter – Westerbeke Marine Generator
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Sierra 23-7800 / 47-237800 – Engine Oil Filter for Westerbeke Marine Generators
Part Number: 23-7800 | SKU: 47-237800
Brand: Sierra
OEM Cross-Reference: Westerbeke 36918
Type: Engine Oil Filter
System: Engine Lubrication – Generator Sets
Keep your Westerbeke marine generator running clean with this direct-replacement oil filter. Built to Sierra's marine-engine application standards, the 23-7800 / 47-237800 is the aftermarket equivalent of Westerbeke 36918 — the factory-specified filter across a wide range of BCG, BEG, BTG, TWG, and SBEG generator families.
Designed for the full Westerbeke generator service interval, this filter traps wear-causing contaminants before they circulate through bearings and other lubricated engine components. Meets or exceeds OEM filtration media quality, bypass valve performance, and thread-fit specifications.
Compatible Applications
- 4.5 BCG / 3.75 BCG
- 4.5 BCGB / 3.75 BCGB
- 4.5 BCGTC / 3.75 BCGTC
- 5.0 BCG / 4.2 BCG
- 5.0 BCGA
- 6.5 TWG / 4.9 TWG
- 7.0 BCG / 5.0 BCG
- 7.0 BCGA
- 7.0 BCGB
- 7.0 BCGC
- 7.2 BCGTC / 6.0 BCGTC
- 8.0 BEG / 6.4 BEG
- 8.0 TWG / 6.4 TWG
- 8.5 BTG / 6.5 BTG
- 9.6 BCGTC / 8.0 BCGTC
- 10.0 BEG / 8.0 BEG
- 11.0 TWG / 8.5 TWG
- 12.5 BEG / 10.0 BEG
- 12.5 BTG / 10.0 BTG
- 15.0 BEG / 12.0 BEG
- 15.0 BTG/A / 12.0 BTG/A
- 20.0 BEG / 16.0 BEG
- 25.0 BEG / 20.0 BEG
- Selected SBEG / SBEGA generator models
Confirm your generator model and existing oil filter number before ordering. The strongest fitment reference is Westerbeke OEM part number 36918.
Service Interval
Replace according to Westerbeke's scheduled oil-service interval for your specific generator model. Refer to your Westerbeke service manual for the recommended interval based on operating hours.
Installation Notes
- Remove the old filter and verify the sealing gasket comes off with it — a retained gasket causes leaks
- Clean the filter mounting surface thoroughly
- Lightly coat the new gasket with fresh engine oil before installation
- Install hand-tight, then snug per Westerbeke service procedures
- Run the generator and inspect carefully for oil leaks at startup
Cross-Reference Part Numbers
- Sierra: 23-7800
- Sierra SKU: 47-237800
- Westerbeke (OEM): 36918
- Wix: 51083
- Volvo: 11715849
- HIFI Filter: T8307
Parts Desk Insights
This filter is primarily a Westerbeke generator oil filter — it is not a general-purpose propulsion-engine filter. The key fitment identifier is Westerbeke OEM number 36918. If you're unsure whether this filter fits your unit, match against your generator's existing oil filter number or the model nameplate before ordering.
Customers servicing a Westerbeke generator often need raw water pump service at the same time. See the Westerbeke Impeller Kit 48500 – Raw Water Pump Service Kit, the Impeller Kit, Westerbeke – Sierra 47-233307, and the Impeller Kit, Westerbeke – Sierra 47-233306 for complete service coverage.
For Onan marine generator oil filter needs, see the Sierra 47-237804 Oil Filter – Onan Marine Generator. For a universal full-flow option, see the Seachoice 50-21021 Full-Flow Oil Filter – 20 Micron.
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.