# 8M0188835 Mercury MerCruiser Cover | Genuine Quicksilver OEM Part ## 🔧 Product Description **Genuine Quicksilver Thermostat and Cooling Water Outlet Cover - Part Number: 8M0188835** A genuine Quicksilver cooling-system cover for selected Mercury and Mariner four-stroke outboards. The component is identified as an oil outlet cover in current Mercury product data and as a thermostat or cooling-water outlet cover in associated engine diagrams. It closes and seals the thermostat or water outlet chamber on the cylinder block, maintaining the intended cooling-water path through the engine. ## ⚙️ Key Features - Genuine Quicksilver OEM thermostat and outlet cover - Correct current Mercury part number 8M0188835 - Supersedes several earlier Mercury cover references - Used on selected Mercury and Mariner 8HP to 60HP four-stroke engines - Cross-references with Recmar, Parsun and Yamaha cover numbers ## 🚤 Compatibility ### Commonly used on - Mercury and Mariner four-stroke thermostat and cooling-water outlet assemblies - Selected Yamaha-based Mercury and Mariner four-stroke engine families - Corresponding Yamaha and Parsun cylinder-block cooling-system applications ### Typically suits - Engine models: - Mercury / Mariner 8HP carburetted Bodensee international - serial 0P086824 to 0P400999 - Mercury / Mariner 9.9HP four-stroke 323cc - serial 0G760300 to 1B226999 - Mercury / Mariner 9.9HP four-stroke international - serial 0P075166 to 0P400999 - Mercury / Mariner 13.5HP carburetted international - serial 0P134638 to 0P400999 - Mercury / Mariner 13.5HP carburetted international - serial 0P401000 and above - Mercury / Mariner 15HP carburetted 2-cylinder - serial 0G760300 to 1B226999 - Mercury / Mariner 15HP carburetted 2-cylinder - serial 1B227000 to 1B727495 - Mercury / Mariner 15HP international - serial 0P075166 to 0P400999 - Mercury / Mariner 15HP international - serial 0P401000 and above - Mercury / Mariner 25HP carburetted - serial 0T409000 to 1B344298 - Mercury / Mariner 25HP carburetted international - serial 0P153500 to 0P388282 - Mercury / Mariner 30HP carburetted 3-cylinder - serial 0T409000 to 1B226999 - Mercury / Mariner 30HP carburetted 3-cylinder international - serial 0P153500 to 0P400999 - Mercury / Mariner 30HP EFI 3-cylinder - serial 0T409000 to 1B226999 - Mercury / Mariner 30HP EFI international - serial 0P153500 to 0P400999 - Mercury / Mariner 30HP EFI - serial 1C109093 to 1C456299 - Mercury / Mariner 30HP EFI - serial 1C456300 and above - Mercury 35HP EFI Jet 4-cylinder - serial 1C453840 and above - Mercury / Mariner 40HP carburetted 3-cylinder - serial 0T409000 to 1B226999 - Mercury / Mariner 40HP carburetted 3-cylinder - serial 1B227000 to 1B344306 - Mercury / Mariner 40HP carburetted international - serial 0P153500 to 0P400999 - Mercury / Mariner 40HP carburetted international - serial 0P401000 and above - Mercury / Mariner 40HP carburetted - serial 1C000001 to 1C018825 - Mercury / Mariner 40HP carburetted - serial 1C018826 and above - Mercury / Mariner 40HP carburetted 4-cylinder - serial 0T178500 to 0T598999 - Mercury / Mariner 40HP carburetted 4-cylinder international - serial 0P094500 to 0P206999 - Mercury / Mariner 40HP EFI 3-cylinder - serial 0T409000 to 1B226999 - Mercury / Mariner 40HP EFI 3-cylinder - serial 1B227000 to 1B355027 - Mercury / Mariner 40HP EFI international - serial 0P153500 to 0P400999 - Mercury / Mariner 40HP EFI international - serial 0P401000 to 0P515896 - Mercury / Mariner 40HP EFI 3-cylinder - serial 1C000001 to 1C043416 - Mercury / Mariner 40HP EFI 3-cylinder - serial 1C043417 to 1C456299 - Mercury / Mariner 40HP EFI 3-cylinder - serial 1C456300 and above - Mercury / Mariner 40HP EFI 4-cylinder - serial 0T409000 to 1B355222 - Mercury / Mariner 40HP EFI 4-cylinder international - serial 0P153500 to 0P400999 - Mercury / Mariner 40HP EFI 4-cylinder international - serial 0P401000 to 0P515896 - Mercury / Mariner 40HP EFI 4-cylinder international - serial 0P515897 to 0P580772 - Mercury / Mariner 40HP EFI 4-cylinder - serial 1C000001 to 1C050251 - Mercury / Mariner 40HP EFI 4-cylinder - serial 1C050252 to 1C453839 - Mercury / Mariner 40HP EFI 4-cylinder - serial 1C453840 and above - Mercury 40HP EFI Jet - serial 1C051324 to 1C453839 - Mercury 40HP EFI Jet - serial 1C453840 and above - Mercury 40HP EFI SeaPro 4-cylinder - serial 1C453840 and above - Mercury / Mariner 50HP carburetted 4-cylinder - serial 0T178500 to 0T598999 - Mercury / Mariner 50HP carburetted 4-cylinder international - serial 0P094500 to 0P206999 - Mercury / Mariner 50HP EFI 4-cylinder - serial 0T409000 to 1B355222 - Mercury / Mariner 50HP EFI international - serial 0P153500 to 0P400999 - Mercury / Mariner 50HP EFI international - serial 0P401000 to 0P515896 - Mercury / Mariner 50HP EFI international - serial 0P515897 to 0P580772 - Mercury / Mariner 50HP EFI - serial 1C000001 to 1C050251 - Mercury / Mariner 50HP EFI - serial 1C050252 to 1C453839 - Mercury / Mariner 50HP EFI - serial 1C453840 and above - Mercury / Mariner 60HP carburetted 4-cylinder - serial 0T178500 to 0T598999 - Mercury / Mariner 60HP carburetted 4-cylinder international - serial 0P094500 to 0P206999 - Mercury / Mariner 60HP EFI 4-cylinder - serial 0T409000 to 1B355222 - Mercury / Mariner 60HP EFI international - serial 0P153500 to 0P400999 - Mercury / Mariner 60HP EFI international - serial 0P401000 to 0P515896 - Mercury / Mariner 60HP EFI international - serial 0P515897 to 0P580772 - Mercury / Mariner 60HP EFI - serial 1C000001 to 1C050251 - Mercury / Mariner 60HP EFI - serial 1C050252 to 1C453839 - Mercury / Mariner 60HP EFI - serial 1C453840 and above - Mercury 60HP EFI SeaPro 4-cylinder - serial 1C453840 and above - Mercury FormulaRace 60 - serial 1C104574 to 1C782687 - Mercury 60R EFI Racing - serial 1C615064 and above - Mercury 60HP 1.0L EFI L4 APX - serial 1C782688 and above - Yamaha F9.9 four-stroke applications using cover 6H3-12413-00 - Yamaha F15 four-stroke applications using cover 6H3-12413-00 - Yamaha F20 four-stroke applications using cover 6H3-12413-00 - Yamaha F25 four-stroke applications using cover 6H3-12413-00 - Yamaha F30 four-stroke applications using cover 6H3-12413-00 - Yamaha F40 and F45 four-stroke applications using cover 6H3-12413-00 - Yamaha F50 and F60 four-stroke applications using cover 6H3-12413-00 - Yamaha F70 applications using cover 6H3-12413-00 - Yamaha 50G, 60F and 70B applications using cover 6H3-12413-00 - HP Range: Mercury / Mariner 8HP - 60HP; corresponding Yamaha applications 9.9HP - 70HP - Engine Type: Mercury / Mariner four-stroke outboard with corresponding Yamaha and Parsun applications - Year Range: Approximately 1998 onward, dependent on model and serial number ## 🔌 Function The cover closes and seals the thermostat or cooling-water outlet chamber. It retains the applicable thermostat and sealing components while directing cooling water through the designed cylinder-block passages. ## ⚠️ Common Signs of Failure - Cooling-water leakage around the cover joint - Corrosion or pitting on the gasket surface - Cracked or broken mounting point - Cover distorted through overtightening - Thermostat chamber will not seal with a new gasket ## 🔄 Supersession & Cross Reference ### OEM Supersession Chain - 8M0188835 → Supersedes 8M0008243 - 8M0008243 → Supersedes 857080 - 857080 → Supersedes / replaces 8250311 - 8250311 earlier OEM cover reference - 825031C earlier related OEM cover reference ### OEM / Related Numbers - 8M0188835 - 8M0008243 - 857080 - 8250311 - 825031C - 07010021 - Yamaha: 6H3-12413-00-00 - Yamaha: 6H3-12413-00-1S - Yamaha: 6H3-12413-00-94 - Yamaha: 6H3-12413-00-9M - Parsun: F15-07010021 - 678633154317 ### Aftermarket / Verified Equivalents - Recmar: PAF15-07010021 - Marine Spare Parts: PAF15-07010021 - Parsun: F15-07010021 ## 📦 Condition - Genuine Quicksilver part - Brand new - Supplied in original or equivalent packaging ## Details - **Price:** 25.45 AUD - **Vendor:** Quicksilver - **Type:** Cooling System - **Tags:** Quicksilver Marine Parts | Oils, Service Kits & Engine Components ## Variants | Variant | Price | Available | |---------|-------|-----------| | Default Title | 25.45 AUD | In stock | ## Images - 8M0188835 Mercury MerCruiser Cover | Genuine Quicksilver OEM Part --- > Source: [Sawley's Auto and Marine](https://www.sawleysautoandmarine.com.au/products/8m0188835-mercury-mercruiser-cover-genuine-quicksilver-oem-part) > Updated: 2026-09-18