If you are indeed talking about the engine water intake, you might consider an upgrade someday. Many years ago I installed a "winterizing" ForeSpar thruhull valve that makes adding antifreeze super easy.
Matter of fact I just did this little task today, and it took less than an hour. I winterized our Betamarine25 (Kubota block, 3 cylinder).
I have the Forespar 3 way ball valve integrated into their thruhull fitting. As per usual for the last two decades, I attach a short piece of hose to the "hose bib" fitting on the top. Drop the other end of the hose into a one gallon bottle of pink "RV" antifreeze. Then warm up the engine. Finally, with the engine idling away, turn the valve from 'outside' water source to the position for the hose connection, and watch the pink liquid start to go down.
Walked back up to the cockpit, and in a few seconds the exhaust burps out some pink water, and I push the stop button. Done, and Done.
Unscrew the hose and put it away. As usual the whole raw water side (strainer, heat exchanger, and water lift muffler) took approx 3 quarts.
Your engine bay will likely required a different arrangement of valving. This change from the EY thruhull locationwas one of the best ideas I have had. Our stock (EY) engine intake valve was under the galley sink and then had a long hose run to the engine pump. Ick.
I was having some discussion with another owner about this part of the drive train. Since we were down at the moorage today with camera in hand.... Here it is pictured with the recent-install split coupler. Also visible is the PSS shaft seal. The...
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