7.4 Merc's - drain plugs ??? Pulled an antifreeze came out

[Soul Mate II]

HELP please. I have 7.4 Mercs with V drives. I read about drain plugs. I found two drain plugs on each engine. I pulled one of them out and antifreeze starting coming out. Do I need to pull different drain plugs? The salt water comes up through the sea strainers for the exhaust. I was going to run fresh water through the sea strainer and then use about 6 gallons of antifreeze into the sea strainer.

Does this make sense?

Thanks for helping!

 

[northern]

We have 454 on a strait drive. I winterized for the first time. Lot of help and threads on the site to help you. With the boat on the hard. I first took out the drain plugs on the mufflers. Then closed the through hull. Then sucked all the water out of the sea strainers. Then poured pink into the sea strainer and the piping until it as full. Then pulled the coil wire off so the engine would not start. Then had the admiral turn over the engine while I pored 3 gallons of pink into each sea strainer. Then after the sea mufflers had drained I put the plugs back in. Probably could have just used 2 gallons per engine but for the extra $5 I sleep better.

 

[Soul Mate II]

Northern, thanks or your reply. My engines are also 454 (7.4 Mercs). I am not understanding where the drain plugs are. I obviously pulled the wrong ones. I like the idea of pulling all the water out as to not dilute the antifreeze

 

[BillK2632]

Need a little more info, but a quick guess is you have closed cooling on your 7.4's - if you do there is a tube (heat exchanger) mounted on the front of the motors (in a v-drive the front of the motors actually faces stern). This means you don't need to drain the engine blocks, just the exhaust systems and raw water cooling system. The engines themselves have antifreeze in them like a car engine. I won't try to give you winterization instructions since I have never actually owned or winterized an engine with closed cooling, just know the basics. If you are not familiar with the process, you might want to find a friend who is to help or pay to have it done this first time (and watch) - winterizing a marine engine is not hard, but you don't want to get it wrong!

 

[northern]

I assume you have closed cooling system with anti freeze. All you need to drain are the black mufflers. They have a drain plug in the bottom. The raw water pump and the areas the sea water go too need protecting. To do that turn the engine over with the coil wire off and pour pink into the top of the sea strainer. When you get pink out the exhaust ports as good as you are pouring in the sea strainer you should be good based on how it worked for me. On this site some one commented that if you can not get to the muffler drain plug remove one of the big exhaust hoes and pour a gallon of pink into the muffler. Based on the 3 gallons I used the mufflers were full of pink when I was finished. If you are not sure what you are doing a few hours of a mechanics time is less than replacing an engine in the spring.

 

[Bt Doctur]

First we need to know what kind of cooling system you have. An engine serial number would be useful.
Before introducing any kind of A/F you should drain the item first and not dilute it.
If your not 100% sure of what your doing to winterize, get help. Otherwise you might be replacing the engines in the spring.

 

[Soul Mate II]

I have a closed cooling system. I didn't find any drain plugs. Do I take a part the heat exchanger? I ran AF through the sea strainer - about 4 gallons and saw pink come out of the exhaust. Is my engine protected if it's a closed system? Anything else I can do?

 

[Henry Boyd]

You should be ok, assuming pink is good enough for your winter temps. This is the way my guy has been doing our engine for the past couple years. The rationale is after more than ten years the drains may be plugged with guck and could trap water. So he runs AF though the flush connector connector. He also closes the sea cocks so no AF drains back out. This protects the water pump and strainer assembly.

Henry


Sent from my iPad using Tapatalk HD

 

[Soul Mate II]

Well last night I had a eureka moment...I compared old pictures of the engines to newer ones (after some work had been done). They eliminated 2 of the blue drain plugs (the ones under the manifolds) and replaced them with 2 brass elbow looking fittings.

I am considering moving these hoses as they are the lowest point on the exhaust. Does this make sense if I already ran pink AF through? I want to be sure there is no water in the system....just pink.

It's a tough because I think I did everything right....Is there another way to test the system?

 

[wellswa]

Well last night I had a eureka moment...I compared old pictures of the engines to newer ones (after some work had been done). They eliminated 2 of the blue drain plugs (the ones under the manifolds) and replaced them with 2 brass elbow looking fittings.

I am considering moving these hoses as they are the lowest point on the exhaust. Does this make sense if I already ran pink AF through? I want to be sure there is no water in the system....just pink.

It's a tough because I think I did everything right....Is there another way to test the system?

I think I mentioned this to you before, if you're not happy with the blue plastic drain plugs I make a stainless steel replacement that will never break when you remove them to winterize the engines. I know that's a problem with the plastic plugs whenever it's time to winterize. Shoot me a pm and I'll send pics and pricing to you.

 

[rcknecht]

There are two blue drain plugs on the close cooling side of my 7.4s... If you drain those, you drain your close AF from your engine, and you DO NOT want to do that. Put them back in, and fill you your HE with AF.... The plugs you need to drain oare on fitting directly under you manifold...

 

[Soul Mate II]

Thanks Rod - all went well today. When I had work done on the engines last time they removed the blue plugs and put in brass elbows. I finally figured it out when I compared two pictures. I pulled the hoses (4) under each of the manifolds...VERY HAPPY that is behind me!