Winterizing the Mercruiser MX 6.2 MPI

[Merc4ever]

I know it's too early for some but boating season ends in August for me. Summing up all the guides / manuals here's what has worked for me in the past and is what I think is important to do:

1. Empty and replace the fuel filter

2. , I warm up the engine on muffs for 5 minutes at high idle (service mode) from a small remote tank with just 1 gallon fuel mixed with 16 ounces of TC-W3 2 stroke oil and the proper amount of good marine fuel stoarage fluid for 1 gallon. I like doing this better over fogging and draining like some say. In the past in other engines I had seals and carbs dry out, leak, sticking linkages... so I found keeping everything in there wet is best. But not with just the alcohol laced fuel be sure to add the conditioner and 2 stroke oil!

3. Shut down and drain water removing all 7 plugs 4 on the left and **3 on the right poking in the holes with a wire to remove dirt.

4. Drain the engine oil after the water has drained then install a new filter and refill with the oil.

5. Refill engine by removing the hoses on the thermostat housing and dumping a 50/50 mix of anti freeze and distilled water. (Easiest way I have found)

6. They say to remove the plugs and spray in oil but I believe the fuel mix covers it.

7. Preform the necessary outdrive maintenance, grease, oil change...

** Seems to me I'm missing 1 on the block on the right side, should there be 2 on the block like the left side? I never found it and didn't have any freeze up problems last winter.

Anyone care to add to / correct my recipe?

 

[Merc4ever]

I just made it into a video in time for winter to help anyone that never did it. You can see it here:

https://www.youtube.com/watch?v=t7K1vX9LnRk&feature=youtu.be

 

[alldodge]

50/50 mix

Only comment is the mix, while 50/50 ethylene glycol and water is good for well below freezing, if there was any water left in the motor, the mix would be diluted further. We all know air doesn't freeze but any water not removed does. So anti freeze is toxic and hope come spring it is recovered and disposed. Could use full strength antifreeze or maybe just some RV -50 stuff poured in and let drain back out should be good.

 

[Merc4ever]

Only comment is the mix, while 50/50 ethylene glycol and water is good for well below freezing, if there was any water left in the motor, the mix would be diluted further. We all know air doesn't freeze but any water not removed does. So anti freeze is toxic and hope come spring it is recovered and disposed. Could use full strength antifreeze or maybe just some RV -50 stuff poured in and let drain back out should be good.

Good point, I always flush my anti freeze out before I head for the lake and if anybody doesn't I totally agree use the RV stuff. As far as the 50/50 I think it's good for like -35 F and where I live we never go that negative so a little extra water in 2 gallons worth of 50/50 probably won't hurt. I do think most water drains out from the bottom plugs or evaporates because the block is so hot when you pre-heat the engine as you can see in the video.

 

[stonyloam]

If you drain out the water properly, you can forget the antifreeze. A block will only crack if it is full ( or very nearly full) of water that freezes and has nowhere to expand. A little bit of water in the block will not hurt anything.

 

[Merc4ever]

If you drain out the water properly, you can forget the antifreeze. A block will only crack if it is full ( or very nearly full) of water that freezes and has nowhere to expand. A little bit of water in the block will not hurt anything.

Years ago I had a OMC 4 cylinder stern drive I would leave the engine sit empty for the winter months but was told that causes more rust build up inside your engine. Antifreeze does have corrosion inhibiting compounds that I believe help with this when 9 months of the year most boats where I live sit waiting for the 3 good summer months.

 

[virginiadragone]

I just made it into a video in time for winter to help anyone that never did it. You can see it here:

https://www.youtube.com/watch?v=t7K1vX9LnRk&feature=youtu.be

Great video! Thanks a million I used it to winterize mine this year and it was a great help. Would it hurt to leave the antifreeze out if I get it good and dry and leave drain valves open to allow air to circulate?

 

[stonyloam]

Years ago I had a OMC 4 cylinder stern drive I would leave the engine sit empty for the winter months but was told that causes more rust build up inside your engine. Antifreeze does have corrosion inhibiting compounds that I believe help with this when 9 months of the year most boats where I live sit waiting for the 3 good summer months.

OK you need three things to make "rust", water, iron and OXYGEN. Ask that person who told you about the rusting of the inside of the block exactly where that O2 is coming from. Any rusting in the block is going to quickly deplete O2 in the block and rusting will stop, just like a candle will go out if you cover it with a bottle. Besides the inside of the block is already covered by a layer of rust that protects the iron from further rusting. Look, you have a block that was full of water all summer, and you are worried about it setting there filled with air for a few months? This is one of the boating wives tales that you see repeated over and over that IMHO are a crock! Just drain it and forget the antifreeze.

 

[HT32BSX115]

OK you need three things to make "rust", water, iron and OXYGEN. ...........................................Look, you have a block that was full of water all summer, and you are worried about it setting there filled with air for a few months? This is one of the boating wives tales that you see repeated over and over that IMHO are a crock! Just drain it and forget the antifreeze.

YES! (actually, you only need iron + oxygen to get Iron oxide.) but this old wives tale DOES get repeated over and over............

My last Mercruiser engine only went 39 years (from new) before I sold the boat..........it was drained every year, never got AF in the block, and it still ran (although it was a bit worn out!!)!

How long do you want that block to last?

Just thoroughly drain the block! Don't waste your time or money pouring anti-freeze in it.........A famous person once said "AIR DON'T FREEZE"

Most of us here tend to agree.................

 

[Merc4ever]

OK you need three things to make "rust", water, iron and OXYGEN. Ask that person who told you about the rusting of the inside of the block exactly where that O2 is coming from. Any rusting in the block is going to quickly deplete O2 in the block and rusting will stop, just like a candle will go out if you cover it with a bottle. Besides the inside of the block is already covered by a layer of rust that protects the iron from further rusting. Look, you have a block that was full of water all summer, and you are worried about it setting there filled with air for a few months? This is one of the boating wives tales that you see repeated over and over that IMHO are a crock! Just drain it and forget the antifreeze.

I wish you were right it would save me the cost of 2 + gallons of antifreeze each year.

I do think it is the warm summer water in the block that takes out the O2 factor for rust to occur. When you remove the water from the block isn't the space then filled with the 3rd component for rust (O2)? Can we also be certain that all cavities in the block are free of water that could possibly freeze and crack that part?

Why does Mercury state in my owners manual "For additional assurance against freezing and rust, fill the cooling system with a mixture of antifreeze and water" If it is a boating wives tale?

 

[stonyloam]

Granted the level of oxygen in water is less than in air, you are constantly circulating hot oxiginated water through the iron block, plenty of opportunity for rust to form. Yeah the two gallons of air in the block would contain about 1.8 grams of oxygen, that would make (if 100% consumed) about 4 grams of Fe2 O3 (rust) in your 100,000 gram block. Not anything to worry about. Water expands about 9% when it freezes, and will crack the container it is in IF that container is full and there is no where it to expand. If you drain your engine any water left in there that freezes will have plenty of room to expand and cause no damage. As for the Merc manual I suspect that was written by the lawyers. If you want to continue using antifreeze I would suggest straight RV (pink) antifreeze which is non-toxic and should protect just as well, and way cheaper. Remember antifreeze will protect to -50, air will protect to.......no need to worry.

 

[Merc4ever]

I sure hope the information found in the Mercruiser manual came from Lake X proving grounds experts and not some lawyer that never touched a dip stick. There's no doubt a closed system with antifreeze in it all the time is much better for your block, I've heard it's not recommend to go to a closed system after a few years running lake water because of the rust that has formed.

If you live in a area that has a chance that the temp will fall below -50 I would go with straight antifreeze. If you don't want to use it that's entirely up to each individual and their circumstances I'm always up for the easiest way of doing things as long as it's not a risky compromise. In my case I will continue to use it unless someone has a logical explanation why it's totally unnecessary.

 

[stonyloam]

Yeah, the main thing is to drain the water out first, then whatever you feel comfortable with.

 

[bspeth]

I like to run the engine after changing the oil and filter to fill up the new filter and make sure it doesn't leak.

 

[bspeth]

Oh and you cant winterize too early, only too late.

 

[biggjimm]

In my case I will continue to use it unless someone has a logical explanation why it's totally unnecessary.

Personally, I thought there were several logical reasons given but you need to do whatever makes you comfortable. I don't think you're going to cause any more or less rust to accumulate inside the engine regardless of what you do or don't do.

I drain my block & manifold, change oil & filter, put stable in fuel & run it until I know it's in the pump & carb & drain the tank of fuel, change lower unit lube & let her sit out in our sometimes -20 + winter & in the spring I go to the gas station & fill up & go to the lake. No fuss. That's what works for me but as they say, you're mileage may vary.

Hopefully, winter will take as long to show up as summer did here, & I'll have another 6 or 7 weeks before I have to "put the boat up". Actually, I just got it running so I hope to have a few more weeks of good weather . Have a great day all. Jim.

 

[littlerayray]

Ice is a block killer how do you know for sure it's drained all the way look at how many boats are for sale because of poor winterization don't tell me anti freeze is unnecessary this will be the 3rd winter I winterize my boat and will use antifreeze in the block it's better to be safe then sorry imho yes boats are expensive especially the maintenance but we all knew that when we all started boating don't forget boat stands for bring on another thousand

 

[HT32BSX115]

Ice is a block killer how do you know for sure it's drained all the way

Most (or all) of those boats that have cracked blocks are not for sale because of "poor" winterization. It's most likely because of NO winterization.....................

You "know" for sure because you remove the block drain plugs and poke a wire/screw driver/or other object in the hole to clear it of rust and other debris.

Many engine blocks crack because some people don't do that simple thing to ensure they have the holes fully open which leaves a fair amount of water in the block...............

Simply pouring A/F into into the block doesn't ensure that it mixes with that remaining water to the concentration required.......... so just pouring it in doesn't save you either. Your first step MUST be draining the block first. If you do the first step correctly, the second step is not needed.

 

[littlerayray]

My mechanic runs my boat up to temp an d then switches a valve on the hose he has a y type connection while the boat is running it circulates antifreeze through the entire system while the boat is running

 

[alldodge]

My mechanic runs my boat up to temp an d then switches a valve on the hose he has a y type connection while the boat is running it circulates antifreeze through the entire system while the boat is running

The only way this is 100% correct is "IF" the boat is run on a tank long enough for all the coolant to circulate long enough to go completely through the block and exhaust. The thermostat does not stay open 100% of the time. The motor would have to circulate in a tank long enough and then the tank water tested.