Good point !
One more addition ..... if you convert the engine from fresh to raw
water cooling you MUST also change the thermostat to one that opens at
135 deg. F. Sal****er will precipitate carbonates (from raw water)
when higher than 150 deg. F. and will foul the internal cooling
passages inside the engine. If you dont change the thermostat then
you must periodically 'pickle' the internal cooling passages with mild
acid (which will also remove engine base metal; alternatively you can
use a commercial descaling organic-acid mix (Marsolve, etc.) that wont
affect removal of the base metal.

With raw water you must remember that if the internals are allowed over
150 deg. F. .... then you are forming ROCKS inside the engine.

Hope this helps.