another boat question (Engine Winterizing)


Old 10-16-05, 12:05 AM
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Join Date: Oct 2005
Posts: 69
Question another boat question (Engine Winterizing)

Hello I was hoping that I could get some assistance on winterizing my stern drive boat if you don't mind. I know where all the plugs and hoses are that need to be removed inorder to drain the thing but my manual also states to use antifreeze in the seawater section of the cooling system. Here is what it says

IMPORTANT: Mercruiser recommends that propylene glycol (a nontoxic and environmentally safe) antifreeze be used in the seawater section of the cooling system for cold weather or extended storage. Make sure that the propylene glycol antifreeze contains a rust inhibitor and is recommended for use in marine engines. Be certain to follow the propylene glycol manufacturer's recommendations.

For additional assurance against freezing and rust, remove the thermostat cover and thermostat. Fill the engine seawater cooling system with a mixture of antifreeze and tap water mixed to manufacturer's recommendation to protect engine to the lowest temperature to which it will be exposed during cold weather or extended storage. Using a new gasket, reinstall thermostat and cover. Tighten cover bolts securely.

I am sure you understand all that reading. On the boat I know where the thermostat is. It is located in the front and top of the engine and has four hoses coming out of it two on both sides (Note: this is the finally step in the manual after you drain and reinstall all the plugs and hoses). If I am reading that right after you remove the thermostat off of the top of the engine you should just start pouring the antifreeze/water blend in the top of the engine until you see it coming up. Is that right?

For a final question they say to replace the gasket but is that necessary if the gasket doesn't fall apart. Thanks for the help.
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Old 10-16-05, 05:39 AM
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Hello: Rob J. Welcome to the Boats, Sailing, Pwc's & Navaigations topic and the Do-It-Yourself Web Site.

If I am reading that right after you remove the thermostat off of the top of the engine you should just start pouring the antifreeze/water blend in the top of the engine until you see it coming up. Is that right?
YES! That is one correct method for that specific engine. Reason why the manufacturer included those instructions into the owners manual and/or service manual. Based upon that info, I reccomend following that advice.

Also YES! Always use a new gasket. Once a gasket is used, it is compressed to form the needed seal. Reuse is more than likely to fail and a leak will occur. Cost wise, it is simply nothing worth that risk while on the water, in my opinion. (IMO)

Others may disagree and they are intitled to do so. But to me reusing any gasket, clamp, hose, etc is not worth any risk of potential or possible break down or engine failure for such an inexpensive item and/or part...IMO

Winterizing info can be found here:

Also on the sites below:

Stern Drive Help With Illustrations:

DIY'S Boat Pages:

Regards, Good Luck & Safe Boating.
Sharp Advice. Boating Enthusiast. Web Sites Host, Forums Monitor, Moderator Hiring Agent & Multiple Topics Moderator. TCB4U2B2B Enterprises.
Regards, Good Luck & Safe Boating.
Old 10-16-05, 03:57 PM
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Join Date: Oct 2005
Posts: 69
Thanks as always for the help. I have some simple questions that I needed just to check out. I am just being carful but I assume that on question #1 it is alright to do that and on queston #2 I should just follow the instructions on the can that I am using. Thanks

1. The instruction manual says to install a quicksilver attachment over water intake openings in gear housing inorder to flush out the cooling system. I don't have this attachment and was wondering if it would be ok if I just used a large bucket under the gear housing with a hose or two running inside it making sure the water is always above the intake openings on the gear housing? Would this be alright?

2. In fogging the engine for storage the instructions say to remove the flame arrestor and restart engine. While operating engine at fast idle (1000-1500), fog internal surfaces of engine by squirting approximately 8 ounces (227 g) of Quicksilver Storage Seal (or if not available. SAE 20W motor oil) into carburetor bores. Stall engine by squirting last 2 ounces (57 g) of Storage Seal (or oil) rapidly into carburetor. Turn ignition key to OFF position. The instructions on the fogging fluid that I bought has different instructions. It says to run motor until it reaches operating temperature and then with engine running, spray CRC ENGINE STOR into each carburetor for approximately 5-10 seconds. Turn ignition off and remove spark plug(s) and spray CRC ENGINE STOR into cylinders. TURN engine over one or two revolutions with starter rope. This will lubricate the pistons, rings and cylinder walls. Spray spark plugs and openings before inserting plug securely. Which instructions should I follow?

Thanks alot for the help. MIKE

Last edited by robj; 10-17-05 at 12:45 PM.

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