Mercury MerCruiser Carburetor Idle Mixture Screw Kit 811539
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Mercury MerCruiser 811539 is a genuine OEM idle mixture screw kit, and current Mercury dealer references show it superseded to 8M0154265. Current listings describe the part as SCREW KIT, Idle Mixture or SCREW-IDLE/SPRING, which is a more accurate SKU-based description than a generic “screw” listing.
Key Features
- Genuine Mercury Marine OEM part number 811539, replaced by 8M0154265.
- Current part description is idle mixture screw kit / screw-idle-spring.
- Current dealer listing shows GTIN 745061303461.
- Current shipping specs are approximately 0.02 lb, 2.00 in. x 1.00 in. x 0.50 in.
Engine Compatibility
The strongest supportable fitment for 811539 / 8M0154265 is carbureted MerCruiser GM-based gasoline engines. Current Mercury where-used references connect it to a broad range of carbureted applications including 4.3L Gen II / Gen+ V6, 5.0L, 5.0LX, 5.7L, 5.7LX, 350 MAG Alpha, 454 MAG Bravo, 502 MAG Bravo, 7.4L Bravo / MIE, 8.2L MIE, and several ski, inboard, Alpha, Bravo, and crate-engine packages.
Serial Number Fitment Notice
Verify fitment by exact engine serial number and the correct carburetor parts diagram before ordering. This idle mixture screw kit appears across many carbureted MerCruiser packages, so serial-based confirmation is the safest way to match the correct carburetor service part.
When This Part Needs Replacement
Replace this part when the idle mixture screw is damaged, missing, bent, seized, or when carburetor service shows the original idle screw and spring are no longer usable. Because this part is tied directly to the idle mixture circuit, problems here can affect idle quality and adjustment. That service guidance is a practical inference supported by current parts descriptions and carburetor idle-mixture references.
Installation Notes
Install 811539 / 8M0154265 only after confirming the correct MerCruiser carburetor application. Since this is an idle mixture screw part, it should be matched to the exact carburetor setup and adjusted carefully during carburetor service rather than swapped in by appearance alone.
Alternate/Superseded Part Numbers
Current sources show 8M0154265 as the active replacement for 811539.
Parts Desk Insight
For carburetor parts like this, the important match is the exact carburetor family, not just the engine size. A quick serial-number and carburetor lookup usually avoids ordering the wrong idle mixture hardware for a similar MerCruiser setup.
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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