beta marine BD722 newbie question re-coolant/zinc anode!

[jaybeegee]

Hi All! I have been a sailing boat owner for the past 5months and still a long way to go but thanks to the tips in this forum making good progress! So I have a question regarding the zinc anode which I was told by a service engineer (supposedly an expert) who I brought to service my engine (model Beta Marine 20HP BD722) that was not used for a couple of years that this model does not use a zinc anode!!! Seems he was pretty wrong with that info and since ordered from the UK for an anode replacement.

My concern is that there must be a lot of corrosive residue sitting inside the cooling system as a result of not having the anode. In fact already have some problems as I am trying to drain off the coolant with little success! If I remove the coolant pressure valve (see pic) with the lid off, there must be some blockage as nothing comes out! Inserting some wire does not help.




I was told I could leave some chemical overnight to clean the inside - any ideas what this is and if it is recommended?

If the blockage remains, how would I clean?

thanks for your help.

Jay

[jaybeegee]

Noob update 2!

Just realised that the coolant blockage is not related to the zinc anode as that is part of the sea water circuit!

[JimsCAL]

Sounds like the fresh water side needs to be flushed. A product available for flushing an automobile cooling system should work fine.

And yes, the zinc protects the salt water side.