Winterizing Merc 350 Mag

[pa_boda]

I have a 2006 Mercruiser 350 MPI Bravo 3, serial no. ow640026 with 150 hours on it. I have been reading several threads and decided to sign up as this site seems to have great information. I have always winterized my old boats (4.3L and 5.0) but they all had the multiple point draining systems. This new 2006 has the 3 point system. I pulled the 4 plugs and lots of water came out but I'm curious how you get wires up into the block and manifold to make sure it isn't plugged up with sand. Or, is it even necessary. Also, I'd like some advice as to whether it is necessary to do anything with the power steering cooling system when winterizing. My manual says nothing about it. If someone can help me out I'd appreciate it.

 

[pa_boda]

Re: Winterizing Merc 350 Mag

Also, if someone knows where I can find a PDF version of the service manual on line I'd appreciate that also

 

[Don S]

Re: Winterizing Merc 350 Mag

Welcome to iboats pa boda.
Moving this to the I/O forum

 

[Don S]

Re: Winterizing Merc 350 Mag

You want manual #31 for your engine from the link below. The manual for your drive is #39. But it isn't live


http://www-alt.mercurymarine.com/mnetdata/sisdata/srvcovr.pdf

 

[pa_boda]

Re: Winterizing Merc 350 Mag

Thanks Don for the link on the service manual

I was told that I should disconnect a couple hoses on that 3 point drain system and run a tie strap into the hole to check for sand. Does anyone know where those two hoses are on a 350 MAG? Or, is it necessary to do so?

 

[Don S]

Re: Winterizing Merc 350 Mag

Forgot about that part of your question, sorry.
Personally, I would remove all the fancy 3 point drain system and use a drain plug that can be removed so you can clean the holes.
I always have to clean out a block drain on even fairly new boats.
Those drains systems look good on paper, especially to those that sell engines and manifolds to replace the freeze cracked ones.

 

[pa_boda]

Re: Winterizing Merc 350 Mag

Is it possible to run a flexible wire or tie strap or something through the drains on the 3 point system and reach the area that can plug up with sand? A service man a a marina told me to disconnect a couple hoses that had "quick disconnects" on them and just run a tie strap up to make sure they aren't clogged up but I dont' see any hoses with "quick disconnects" on them

Have those 3 point drain systems been in use for a long time?

 

[Dakota47]

Re: Winterizing Merc 350 Mag

Nope.. you need to get at each drain plug, Then poke a piece of wire up in there while draining..

 

[pa_boda]

Re: Winterizing Merc 350 Mag

so there isn't even a hose to disconnect what will get you close enough to run a wire up there?

Am I justified in being worried about this?

 

[Don S]

Re: Winterizing Merc 350 Mag

Am I justified in being worried about this?

Absolutely you're justified.

Merc makes so many little changes to things without mentioning to anyone, or putting it in a manual, that it's almost impossible to keep up with the changes to the draining systems short of looking at each and every one that come thru the shop and knowing what to look for.
I work on these for a living and in the last 5 years, they have gone crazy with gizmo's that cause more problems than they cure.
They look good on paper, just don't work in real life.

 

[Bondo]

Re: Winterizing Merc 350 Mag

so there isn't even a hose to disconnect what will get you close enough to run a wire up there?
Am I justified in being worried about this?

Ayuh,.......

I Agree with Don,+ Dakota,.......

The 1st thing I'd do if your boat was Mine,...........
Is to Remove All of that Fancy Smancy 3 point Clogging System,+ Give it the Float Test at the dock...........

Then screw in some Brass Drain Plugs to fill the holes left behind..........

Then you can knock the Crud out of the Block,+ Manifolds so they Don't Freeze............

But that's just My Opinion..........................................

 

[Don S]

Re: Winterizing Merc 350 Mag

But that's just My Opinion..........................................

It's not just your opinion, just the ones that know for sure, and the ones that have already found out the EASY ways of preventing freeze damage is only about a 50/50 chance of working....... at best.

 

[pa_boda]

Re: Winterizing Merc 350 Mag

I think I read on one of the posts that putting anti-freeze down the thermostat, hoses and sucking it through the lower unit won't protect you either if it is plugged? Is that correct?

How cold and for how long does it have to get before you can crack a block?

 

[Lou C]

Re: Winterizing Merc 350 Mag

Pouring AF down the thermo housing or trying to suck it up the drive, really isn't going to help if the engine is not properly drained in the first place, so whether or not a person wants to use AF, the main point is that it has to be drained, thoroughly, first. Those quicky drain systems don't stand a chance of working in salt water I can tell you that. Every year I have winterized my raw water cooled salt boat, there has been at least one drain plugged by rust and/or sediment. If I was depending on that system to drain it, I'd have bought more than one engine by now. I'd take it all off, and do it the right (old fashioned) way. Get the brass plugs with the wingnut ends and put some marine grease on the threads, mine come out by hand every year even with 6 months in salt water.

 

[Bondo]

Re: Winterizing Merc 350 Mag

How cold and for how long does it have to get before you can crack a block?

Ayuh,............

1 of My Mentors claimed that 26* for 6hrs would Split most cast iron blocks..........
And even though I always took that man's word as the Gospel,.........

I know that Water will get Rock Hard at 31*,...............
The How Long question has too many variables to be considered.............

I start Draining My iron about the time the Weatherman starts speaking of lower 30ish temperatures...........Period........

 

[pa_boda]

Re: Winterizing Merc 350 Mag

Thank you for your input. I'm not sure what I should do now short of pulling all that 3 point drain system off. But there must be a bunch of boats out there with it on. The marina mechanic told me to pull of those 2 little hoses that drain into the lower hose that ends up at the distribution housing and run a long, thick zip tie up it and see if there is any sand up there.

Do you only have to worry about the block or does sand and rust build up in the manifolds too?

 

[jabberw0cky]

Re: Winterizing Merc 350 Mag

All that the 3-point drain system does is replace the drain plugs at their usual drain points with a section of tube that connects up with larger tubes that all eventually lead to your Water Distribution Housing (see page 6b-7 of service Manual 31 linked to earlier). The idea being that you save time by having fewer drain plugs to pull when you want to drain your system. The problem with this is that due to the fact that you're pulling raw water through your engine to cool it, you will occasionally get sediment traveling through the cooling system and it could build up enough to plug the drain points on the block, etc.

Go ahead and use the 3 point drain system as it's designed (one plug on the Water Distribution Housing, two on the seawater pump). Then, once you've gotten all of the water out of it that you think you can - go the extra step of following the tubing from the Water Distribution Housing back to the drain ports on the block. The tubing should connect to a drain point on the port and starboard sides of the block. You'll also have a drain point underneath each exhaust manifold which will be connected via tubing into the whole system. Disconnect the tubing at each point and use a short, stiff wire to poke up into the drain ports and clear any sediment that may be blocking the drain port and see if you can get any more water to come out.

Once done, replace everything, and then remove the thermostat housing and fill the cylinder block and head with propylene anti-freeze.