Sierra Adaptor, Lower Unit, Mercruisr | 18-99536
Free returns on all eligible orders
You have 30 days to request a return. All sale items are final sale.
Sierra Lower Unit Fill Adapter
Lower-unit filling adapter for the specified compatible MerCruiser service application.
- Manufacturer part number: 18-99536
Parts Desk Insight
Match the adapter to the exact drive and service-pump connection. Confirm the port thread before use; this tool is not an engine-installed replacement part.
Shipping information
In-stock and OEM parts: ship same or next business day.
Available items are ready for pickup or shipping between one and three 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.