Yam 15hp 4 stroke flushing attachment

[Blankton]

Hi All, A bit of a question about flushing my engine. I have a 2019 yamaha 15F four stroke engine. I have always flushed it in a bucket.

I am aware that there is a flushing attachment, but it is unclear from the manual what this does. The pipe goes into the upper leg. I was unsure if this was just flushing the pipework or if it went round the block as well (I wasn't sure how this would work as the cold water would close the thermocouple). Hence why I have always used the bucket method, but it would be nice to flush with a hose, if it will be just as effective.

I have just tried it and water comes out of the tell take, prop centre, and three drains on the lower leg. I don't know if this gives any clue as to the flow? I'm a bit lost on this engine because all the lines are the same 10mm black pipe - water, fuel, even the electrical wires are in a very similar looking conduit, so its quite hard to trace the "plumbing"

Tel tail:


Prop:


Three drains. One fore and one either side:

[Ferryman]

I have a Mercury Verado and that has to be flushed with the attachment. As far as I know, Yamaha is fine with the hose connection and the engine can be raised or lowered.

[Blankton]

Originally Posted by Ferryman

I have a Mercury Verado and that has to be flushed with the attachment. As far as I know, Yamaha is fine with the hose connection and the engine can be raised or lowered.

Thanks. It would seem a pretty stupid design, if it didn't flush the whole water jacket. I just couldn't work out how it bypassed the thermostat

[Ferryman]

Originally Posted by Blankton

Thanks. It would seem a pretty stupid design, if it didn't flush the whole water jacket. I just couldn't work out how it bypassed the thermostat

I’m supposed to be a marine engineer but much bigger engines.
I don’t know the answer to that one, I usually wash the engine through while it’s still hot but if I don’t, water still flows from every orifice so I assume it’s working!