All of these OHC 4's have a Closed Cooling system, much like the radiator used in cars/trucks, but dumps the heat into the sea water.
The Red unit that you see, is the Heat Exchanger.
Read up on what you can about Marine Engine Cooling pertaining to this engine.......... This is very important.
Be very careful when removing any fasteners...... you may have some corrosion that makes breaking and/or stripping bolts/threads very easy.
These are expensive parts.... go slowly.... use heat where needed if in question.
Penetrating oils often take weeks to enter threads..... and even then, it's a crap shoot........ heat is your friend.
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