Raw water flush(no heat exchanger)...

[stephen_h]

I am sure this has been asked before but I couldn't find it.

I have a raw water cooled Yanmar 3GMC. No heat exchanger - thats on the other engine.

I recently had to remove/replace the thermostat and found it covered in limescale.
I cleaned it all okay but now I want to give the engine a flush with some Rydlyme.

I can see where the raw water goes into the exhaust manifold but then it only exits out
of the boat and over the side. I know it splits off when the thermostat opens but not sure
how I can set up a way to pump the Rydlyme around the whole system without it going
straight over the side?

All the diagrams / Youtube videos show flushing an engine with a heat exchanger fitted.

Anyone done this?

 

[vyv_cox]

There are many posts on the topic on this forum. A good search will find them.

There is no need to circulate acid, cold hydrochloric poured into the thermostat housing will clear all scale in 10 minutes. Some have used other acids, phosphoric for example.

If you really want to do it hot you can collect the acid exiting the exhaust and return it to the pump. Temperature needs to exceed thermostat opening figure to ensure acid enters the engine, not the bypass.