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View Full Version : Thoughts on draining the block/manifolds every time out?


Kevin 89MC
10-21-2005, 10:15 AM
Now that I have the new brass block & manifold drains, draining them is so much easier! Does anyone drain them after every run, or do you all just leave them closed until winterizing? I was thinking it may be better to drain every time (or at least often), so water doesn't sit, but I suppose you never get all the water out, so maybe there is no real benefit. It might cut down on the rusting some, but I've never really noticed too much rust inside anyways. Thoughts? :popcorn:
Kevin

erkoehler
10-21-2005, 10:29 AM
I think it is an unneccessary step during the season, unless you were to leave your boat for months on end without use. Just remember to put those plugs back in before you fire up the engine. I could definetly see people doing that if they were in a hurry or excited to bee on the water.

east tx skier
10-21-2005, 10:54 AM
I agree with Eric. I'd forget to close them up. Those cast iron manifolds are just going to rust some. But it will take a long, long time for them to rust through. I'm at 13 years and counting on mine. They have some rust on the inside, but they're still going strong. In my opinion, it won't hurt assuming you never forget to close them up (and closing them up after you drain will still leave water in there, where it's hot ... condensation). But it's probably overkill.

whitedog
10-21-2005, 10:58 AM
It takes mosture and oxegen to cause rust. By draining the manifolds and allowing air in the water passages you will encourage rust. :(

That is one of the reasons for the use of antifreeze when winterizing.

88 PS190
10-22-2005, 01:51 PM
i agree w/ white dog, an engine full of r/v marine antifreeze- the pink stuff is a safe engine, it keeps the surfaces wet (protected) and any water present in the system is going to be taken up w/ the antifreeze and suspended.

Smoothest set up i've seen for this was a bin of antifreeze placed behind the exausts to catch the antifreeze, then a bilge pump w/ a car battery, so that the pump can be connected to the battery, and then uses hose to connect to either a fitting to your inlet hose, or a fake a lake system, then the engine can be run let idle up to temp all the galleries will be filled, the thermostat open etc. and the extra antifreeze ends back in the bin. Kinda an extensive system if you only do one boat, but if you have a few boats, neighbors etc, one set up can be used over and over, just adding an occasional gallon or so of antifreeze to the tub as it gets drained. And it works for inboard outboards if you add one of the muff set ups and lower the stern drive over the bin to catch the output.

mitch
11-10-2005, 12:57 PM
It takes mosture and oxegen to cause rust. By draining the manifolds and allowing air in the water passages you will encourage rust. :(

That is one of the reasons for the use of antifreeze when winterizing.

If that's the case why doesn't MC list the antifreeze in the winterize checklist? Is the pink stuff even a true rust inhibitor like the green kind?

88 PS190
11-10-2005, 01:07 PM
If its not the case why do most mastercraft dealers use antifreeze when they winterize?

Its just a good failsafe, rather have Pink in, then water.

Hoff1
11-10-2005, 01:30 PM
I agree that you shouldn't drain and leave empty. That would promote rust in my opinion. RV antifreeze does have rust/corrosion inhibitors.

mitch
11-10-2005, 02:22 PM
[QUOTE=88 PS190]If its not the case why do most mastercraft dealers use antifreeze when they winterize?

How do you know this?

mitch
11-10-2005, 02:27 PM
Standard RV and Marine antifreeze formulated specifically for winterizing application only should not be used in the RV heater hydronic system. Because this type of antifreeze does not contain rust inhibitors, it is not designed to transfer heat, which is essential to the heating system function.

Just found this, and it's not the 1st time I read this.

OhioProstar
11-10-2005, 02:37 PM
I think Kevin was asking about between sets during the season.

Kevin, If you are using the boat late in the season it would be good to drain just in case MSP falls below zero at night. During the season I wouldn't worry about draining every time. If all the water is removed it might be harder on the waterjackets then if you have the block full from the last outing. Plus ErK is right....it is one more thing to remember and as everyone with a lot of hours will tell you...You will forget the plug once and a while, so don't mutliple your chances.

Cloaked
11-10-2005, 03:36 PM
Thoughts? :popcorn:
KevinStop the madness. :uglyhamme

Use the boat for crying out loud... :D :D

Kevin 89MC
11-10-2005, 05:21 PM
Yeah, I was talking about during the boating season. After I posted I also thought that it may actually encourage more rust because of more air inside & less items submerged. Just a little excited about the new drain plugs I installed, with it being so much easier to drain everything. I do drain the block at the end of the season when it may get below freezing at night but I may still use the boat before winterizing. Happened this fall twice!
Kevin

boatless
09-20-2006, 12:22 PM
Kevin,
Where did you get the brass fitting and do you have a picture of it ?

Thanks,

boatless.

bigmac
09-20-2006, 12:45 PM
Kevin,
Where did you get the brass fitting and do you have a picture of it ?

Thanks,

boatless.

You mean these?

http://www.skidim.com/images/mcm000.jpg

I'm not sure brass petcocks are a good idea. The opening is smaller than than the drain hole in the block, making them more likely to be plugged with rust. Removing the plug completely takes about 10 seconds with a socket wrench, and you only do it once a season. Note that MC is very clear that even when removing the brass plug, you should poke the hole in the block in case of rust or scale preventing complete block drainage. That problem is going to be magnified with the smaller opening in the brass block drain leading to an increased possibility that the block will be incompletely emptied.

Also, if your engine is fuel injected IIRC there's a knock sensor in one of those drain holes, and you can't replace it with a petcock.

east tx skier
09-20-2006, 01:54 PM
Replaced the petcocks on mine with ordinary brass plugs. Easy to remove and no worrying that the petcock is blocking flow.

Brn85ss
09-20-2006, 02:20 PM
I use the petcocks on mine they work like a champ.Nice for extending the season.I don't worry about leaving them open just part of my pre launch routine.I think the manifolds rusting has way to many variables to even make a strong point either way.I still pull them when I winterize and I will say the large flakes of rust are not there.I think the rust flows out of the petcocks in smaller pieces after each run.