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Winterizing my 76' twin 350 engines

roguenc

New member
I purchased my boat this july, and am now going to winterize it. Unfortunately I dont have a manual telling me how to winterize the 76' era 350's.

Some guys on the dock are saying there are bolts under the mainifolds that you drain them out from. I find it hard to believe since they rise above the body of the engine and not below where the low water area would be.

Can anyone help me out on this.

Thanks
 
According to service manual for raw water cooling the drain points should be:
Oil Cooler
Raw Water Pump Cover
Drain plug at aft ends of exhaust manifolds
Drain plugs on port and stbd side of engine block (brass plugs beneath manifolds)
Hose from circ pump
Thermostat from housing
 
Thank you for that. Is there a place I can get the service manual that you wrote about? Does the manual have drawings/pictures showing these locations?

Thanks
 
According to service manual for raw water cooling the drain points should be:
Oil Cooler
Raw Water Pump Cover
Drain plug at aft ends of exhaust manifolds
Drain plugs on port and stbd side of engine block (brass plugs beneath manifolds)
Hose from circ pump
Thermostat from housing
Good points!
These will all be what are called "low point" drains.
If you can warm the engine first, you can loosen these with less risk of trouble. Drain when the engines cool again!

If you plan to install anti-freeze in the engine block/heads/manifolds, be sure to drain afterwards. The risk would be residual sea water that does not become thuroughly mixed witht he anti-freeze.

And always probe your drain ports with a wire or ___ to remove any rust scale/debris.

But don't get ahead of yourself here.
You also want to stabilize your fuel in the fuel tank.
Talk to your marina people regarding what they would recommend.
Your fuel filter cartridges can be filled with a rich mixture of this, then be re-installed, and can be introduced into your fuel deliver system (carburetors, for example) as you run the engines.

Old alkalinic/acidic contaminated engine oil should not be left in. Great time to change oil/filter!

Fogging your carbureted engines is last on your list!
Note that any "dual plane" intake manifold MUST receive an equal amount of fogging solution at each plane, as to enter all cylinders! If this is not equal, then 4 cylinders will be less protected.

Fogging can also be performed in as little as 8 to 10 seconds (@ 1,200 rpm), of which means that this can be done (if careful) with your sea water impellers removed!
(unless this presents an issue with a moored boat!)
This is considered a quick "dry-start" and also removes the risk of water within the exhaust system.
I've been doing this for years, and can tell you first hand that it works well. Experience... not speculation!
However..... your call!

Have a helper kill the ignition as you continue to FOG. This prevents combustion during the last of the fogging procedure. I beleive that we get better protection this way!

One point re; sea water pumps:
To me, this is the wrong time to install new sea water pump impellers!
There is no reason to install a new impeller that will sit inside of a pump body, with three/four blades folded against the cam, for this Non-Use duration.
Save this step for your Re-Commissioning in Spring time!


The most important words: Air alone won't freeze/expand and cause damage! :D

Good luck!
 
Last edited:
Tonight after work I head to the lake to do what youve both suggested. I will report back later on on what I found out and was able to accomplish.

Thanks
Tom
 
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