New Owner Winterization Lesson Learned

[nrpolo]

Just bought a 2003 2100 SD with 135 original hours. Family needed a bigger boat to haul around the kids and their friends. My other boat is a 16' Starcraft Super Sport so new to inboards. Got her home and decided to winterize. Has the Single Point system. After doing some research I took the advice of not trusting the system. Removed thermostat housing and disconnected the quick release fittings on the block drain hoses. Poured in antifreeze and port drained fine, nothing from starboard. Took a 3 1/2" deck screw and reamed the fittings. Starboard totally blocked and took a lot of effort to get the screw into the fitting. Lots of rust came out and now she drains great. Hopefully a disaster averted on my new investment. Glad for great forums like this one that share experiences and past lessons.

[donald]

Welcome
Please post year and engine,drive info in your signature as it helps us to help you.
Glad you did it right and avoided a problem down the road.
Enjoy it and good luck.
Don

[mmwjr]

Yes that is a flaw with Mercruisers single point system especially for salt water boats. Another concern is for those that use a winterizing kit that is filled with antifreeze and attached to the drive with muffs to flush the engine. What's over looked is the engine must be fully up to operating temperature first otherwise the thermostat is closed and the antifreeze will not pass through the engine but only the exhaust resulting in a cracked block.

[nrpolo]

Yep, very glad I didn't buy and use the muff kit from Amazon. Do manifolds ever trap water from rust? Seems their openings are a lot bigger then the block drains.

[donald]

I have a 5.7 with a half closed cooling system and I remove the hoses from the manifolds to drain them. also remove the hoses from the P.S. Cooler as it is plumbed into the sea water hose for cooling the P.S fluid and engine.
It should be on the port side of the engine under port exhaust manifold remove both hoses so it will drain all water.
Don

[mmwjr]

Originally Posted by nrpolo

Yep, very glad I didn't buy and use the muff kit from Amazon. Do manifolds ever trap water from rust? Seems their openings are a lot bigger then the block drains.

Being a larger and a bottom drain the manifolds are not as prone to scale blocking the hole like the engine drains. These are car engines and were not designed for raw water cooling and using those drains for annual maintenance. When I had to repower I added a half closed cooling system, best boat buck I spent.

[nrpolo]

Will do that. Thanks for all the great info.

[MoonRiver]

Ok, what is a "half closed" cooling system?

Yep, I learned a lesson this winterizing year too. While I thought the engine was warmed up enough to allow the Pink to flow through the block, it wasn't. When I shut it down and started opening the petcocks only clear water came out!!! Its a good thing I always drain the block, PS cooler and manifolds after flushing with pink.

[mmwjr]

Originally Posted by MoonRiver

Ok, what is a "half closed" cooling system?

Yep, I learned a lesson this winterizing year too. While I thought the engine was warmed up enough to allow the Pink to flow through the block, it wasn't. When I shut it down and started opening the petcocks only clear water came out!!! Its a good thing I always drain the block, PS cooler and manifolds after flushing with pink.

A half/partial closed cooling system only cools the engine through a heat exchanger while a full closed cooling system cools the engine and exhaust manifolds, the elbows are still raw water cooled.

This closed loop through a heat exchanger is filled with an antifreeze mixture just like a car. The only difference is the HE on a boat is liquid to liquid while a car is liq to air. In other words raw water flows through the HE to remove the closed sides heat.