Flushing muffs

[TheOldDuffer]

Made a schoolboy error and bought flushing muffs too big to fit the Yamaha 6HP. Anyone a recommendation for ones that would fit?

[TheOldDuffer]

I think a bucket of water set on blocks may be the only answer.

[Llafurio]

Make it a big bucket.
- I use one semi-flexible garden container (Aldi), 60 ltrs. I use the jockey wheel as jack to dip the engine in deeper. Works perfect.

[garethrow]

Yamaha sell a specific adaptor that screws into the wash port low down on the shaft near the prop - adjacent to the oil filler port screw for gear oil. You unscrew the 'wash' screw and screw in your adaptor that clips onto your hosepipe with a hoselock connection. I use this every time after I go out on salt water and run the engine (6hp Yamaha) for 2 to 3 minutes. Don't confuse the screws! They are clearly labelled.

Gareth Rowlands
GRP BR20 Halen Y mor

[MarkF]

I’ve always wondered if there is a ‘best’ method for flushing the outboard. The hose adaptor is convenient but the bucket-of-water approach ensures the prop and inlet get a good wash.

Although there’s only one inlet on the 6hp, there are vents on both sides, so I wasn’t sure how well the muffs will work.

Anyone got a recommendation?

As far as I can find, Yamaha says the following:

“Testing has shown that even the flush attachment method allows water to pass into the cylinder head passages, in spite of the fact that the thermostat does not fully open. This means that there is no disadvantage to using the flush attachment.

While conventional wisdom might indicate there is some benefit to flushing with the engine running—such as with flush muffs or a flush bag—there is no clear data to indicate this is true.“

[Sea Simon]

Imho...and I'm  a Charteered Marine Engineer (Yes, there is such a thing!)...albeit generally based on rather larger engines.

If you're not running the engine while Flushing, you're wasting your time. At least try to get the thermostat to open....if only partly.

It's really all about Flushing out the narrow salt water cooling passages in the cylinder head, and block etc. The prop/leg wash (prop is often plastic these days) is very much a side show. Salt will deposit in hot, narrow passages and eventually kill your engine. Mechanical cleaning almost impossible on small engines. Chemical cleaning can be risky (be very sure to dissolve deposits, not your engine!).

Bucket of water, muffs, or screw in inlet adapter  are all good.
Just be very sure you are getting a good flow of fresh water out of the "tell tale". Job done.

[MarkF]

Note: The Yamaha guidance states that when using the flush attachment you don’t run the engine - hence their qualification about the thermostat not being fully open.

[Sea Simon]

Sounds like this screw in adapter may bypass/not feed the water pump? Agreed, don't run motor.

Bucket method is my favourite, as it allows motor to lift fresh water "naturally ", as designed, with no risk to engine from overpressure on forced water supply.

[TheOldDuffer]

Bucket flush this morning, though I didn't run it long enough to get hot. I should have done it earlier - is it really necessary to do it each time?