MerCruiser Engine Cleaner - 858080K03
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Mercury 858080K03 is a genuine OEM Power Tune Internal Engine Cleaner in a 12 oz spray can. Mercury describes it as an internal engine cleaner formulated to break down and remove carbon, gum, and varnish deposits that build up from normal use, low-temperature operation, or certain fuels.
Key Features
- Genuine Mercury Marine / Quicksilver OEM product
- Part number 858080K03
- 12 oz / 340 g aerosol spray can
- Helps remove carbon, gum, and varnish deposits
- Intended to help restore fuel and air flow and improve overall engine performance.
Engine Compatibility
Mercury states this cleaner is safe for all 2-stroke and 4-stroke carbureted and fuel-injected gasoline engines, including catalyzed engines. That makes it suitable for a broad range of Mercury and MerCruiser gasoline applications when used as directed.
Serial Number Fitment Notice
This is a maintenance chemical rather than a model-specific hard part, so serial-number matching is generally less critical than it is for mechanical components. It should still be used only on compatible gasoline engines and according to the engine’s service guidance.
When This Part Needs Replacement
Use this cleaner when the engine is showing signs of performance-robbing combustion-chamber deposits, or as part of maintenance when carbon, gum, or varnish buildup is suspected. Mercury specifically positions it as a way to help restore lost power caused by these deposits.
Installation Notes
This is a spray-applied internal cleaner. Use it only as directed for compatible gasoline engines. Mercury’s product guidance centers on cleaning internal deposits in the combustion chambers and fuel/air path to support better running performance.
Alternate / Superseded Part Numbers
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92-858080K03
Some seller listings also reference a closely related Quicksilver version, but the correct Mercury OEM number for this listing is 858080K03.
Parts Desk Insight
Power Tune is the kind of maintenance product that can make sense when an engine has seen lots of idling, cool running, or fuel that leaves deposits behind. It is aimed at cleaning the inside of the engine, not just the outside of the fuel system, which is why Mercury ties it directly to lost-power complaints caused by combustion-chamber buildup.
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.
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.