Re: winterize searay with mercruiser 7.4/bravo 3
I have a 2001 270DA. This is what I do. Add fuel stabilizer. Fill fuel tank to top with no-ethanol gas. Change engine oil. Change oil filter. Change Bravo III oil. Remove the 5 (I think) drain plugs to drain water out of engine (2) and manifolds (2) and PS cooler (1). Make sure you poke a piece of wire into each hole. Accumulated crud often keeps all the water from draining. Remove the hoses from the raw water pump and the "cool fuel" heat exchanger if you have one and drain water. Replace all hoses and plugs. Turn on onboard water pump and let it run until all water is pumped from the water tank. Open all faucets and the water heater drain and let all water out. To make sure all water drains out of the water heater, open the relief valve to let air in.
Something many people forget is to purge the head and holding tank. I flush the head around 10 times with clear water to (hopefully) remove all solids from the pipes, hoses, and vacuum system. If you don't do this, you may have a bad surprise next spring when you (try to) flush the head. Then I open the Y valve and pump everything possible out of the holding tank. Finally I put a gallon of pink propylene glycol antifreeze in the toilet and flush it. This puts antifreeze in all the pipes and hoses that you cannot (don't want to) unhook and drain.
I made an adapter from a piece of hose and fittings that I can hook to my air compressor. One end is connected to the air compressor and the other end is connected to the dockside water inlet on the rear of the boat. With around 30PSI of air pressure I open all faucets and purge the entire water system with compressed air until nothing but air comes out of any of the faucets and the water heater. Don't forget to purge water out of the transom rinse-off shower, and wash down faucets if you have them. Also operate the head (toilet) water flush valve a couple of times to purge all water from it. (Ask me why)
Then I take the same compressed air adapter, add another home made piece, and insert it into the AC water OUTLET on the port side of my boat. With around 10PSI of compressed air, I purge all water out of the AC condenser, hoses, and the AC water pump with compressed air. You have to manually drain the AC water strainer. The water is expelled out of the sea water pickup under the boat. I have a centrifugal water pump on my AC. Don't do this if you have a flexible impeller AC water pump. You may destroy an impeller type pump with compressed air.
I know all this sounds as if it will take forever to do. Total time from start to finish is less than 4 hours. Once the engine water is drained, engine oil and filter are changed, and once the Bravo III oil is changed, everything else takes less than an hour. But I have been doing it since 2001.
