Double Feed Outboard Flush Muffs Round Cups Hozelock MMS-426-GS30351
mms-426-gs30351
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Double-Feed Round Outboard Flush Muffs
Extended cups | Hozelock-compatible connection
A twin-feed flushing attachment with extended round cups and a Hozelock-compatible water connection for compatible outboard lower-leg side intakes.
Key Features
- Feeds both sides of the lower unit
- Extended round rubber cups
- Hozelock-compatible quick connector
- For 12 mm water-hose systems
- Recommended product class for engines above 30 kW / 40 HP
Technical Specs
| Feed type | Double / both sides |
| Cup shape | Extended round |
| Hose system | 12 mm (0.47 in) |
| Connector | Hozelock-compatible |
| Supplier recommendation | >30 kW / 40 HP class; verify intake fit |
| 4Boats SKU | mms-426-gs30351 |
Compatibility / Fitment Guide
These muffs are selected by intake position, cup size and water-supply connection — not by horsepower or brand alone.
| Compatible intake layout | Opposed side intakes on the lower leg that sit fully inside the extended cups. Not suitable where the cups leave any active intake uncovered. |
| Cup fit | Both cups must sit flat and fully cover every side intake slot. They must remain sealed when water pressure is applied; damaged, painted or unusually shaped gearcases may not seal. |
| Check for extra intakes | Not suitable by itself for nose-cone, low-water-pickup, under-cavitation-plate or other uncovered intake designs. Follow the engine manual for taping/closing additional inlets or using the specified adaptor. |
| Water supply | Connect to a compatible Hozelock-style coupling on a 12 mm supply hose. Lock the coupling fully and confirm it cannot pull free under pressure. |
| Engine operation | Do not start the engine merely because muffs are fitted. Run only if the manufacturer’s flushing procedure explicitly permits it, with the gearcase vertical, gearbox in neutral, propeller area clear and a strong continuous water supply. |
| Not for | Sterndrives or inboards unless their manual specifically permits this muff arrangement; engines with a dedicated flush-port-only procedure; frozen/damaged cups; unattended running. |
Part Number Cross Reference
| Flusher style | Double-feed extended round-cup muffs |
| Water connection | Hozelock-compatible / 12 mm hose |
| 4Boats SKU | mms-426-gs30351 |
No OEM engine part number is claimed. The engine owner’s manual and the physical water-intake layout determine compatibility.
Frequently Asked Questions
Will these fit every outboard?
No. Both cups must cover the complete intake pattern and the engine manual must allow muff flushing.
Can I run the engine while flushing?
Only where the engine maker’s procedure expressly allows it. Never run without visible cooling-water supply and never leave the engine unattended.
Should the propeller be removed?
For workshop running, removing the propeller is the safest approach where the manual and service procedure allow; otherwise keep the area completely clear and ensure neutral is positively selected.
Why is no tell-tale visible?
Shut down immediately. Check water pressure, cup seal, blocked tell-tale and the model-specific procedure before trying again.
Allow the engine to cool, keep people clear of moving parts and hot exhaust, and never rely on muffs that do not seal positively over all required intakes.
For the products under £150 the shipping is £6.99.
Free delivery for most items over £150.
