purging water from the 496 cooling system
 

I've got a new to me boat- ordered the manual, but not here yet- will be colder here in a few days- how do I evacuate the water from the closed cooling??

Re: purging water from the 496 cooling system
 

Take off blue pump snapped on heat exchanger. Fit on valve and pump
until tabs pop out,water will release from bottom.
***Caution,this is only for cold days in your season. Winterize with
antifreeze when putting boat up for the winter****

Re: purging water from the 496 cooling system
 

Just expand on what epeek said....there's two little green tabs that pop out. The first one pops out after a few strokes on the pump. Make sure you keep pumping till BOTH tabs pop out.

Also, I unscrew the blue plugs on the "cool fuel" system. Even after pumping the water out as described above, a little water still comes out those blue plugs.

Re: purging water from the 496 cooling system
 

use a small air compressor, I do and it'll put enough air in the system to blow all the water out as well as sand blockage from the drains. Those hand pumps are a joke.

Re: purging water from the 496 cooling system
 

The Merc 496 hand pump system only pressurizes the two air valves that then actuate/open the sea water drain valves which then allow the sea water to drain by gravity from the heat exchanger, cool fuel system, exhaust manifolds and associated plumbing. The engine block is part of a sealed antifreeze system.

Re: purging water from the 496 cooling system
 

what about the 2 little blue wingnut drains on the lower left? drained those, are there more? I have thru hull fittings under thengines- should the system self drain by design?

Thanks for the help guys....

Re: purging water from the 496 cooling system
 

The blue wing nuts drain the remaining water in the cool fuel system and the sea water pump, etc. that does not drain out with the air solenoid drain valve system described above. I believe there are three, two on one side and another on the other side but not positive.

Re: purging water from the 496 cooling system
 

5 total blue drain plugs per engine.

2 on water pump assembly.

Re: purging water from the 496 cooling system
 

Your kidding right? :rolleyes: So that's what that pink stuff was draining into my bilge???



Use compressed air to assure complete opening, and save some time.

try it you'll like it.

Re: purging water from the 496 cooling system
 

This year after purging all water out and pulling the blue plugs,and them reinstalling them, I ran rv antifreeze with ear muffs and then just left it in there.Won`t be a dry start next year..its good for -18.

Re: purging water from the 496 cooling system
 

;) :)

Re: purging water from the 496 cooling system
 

I found the 2 on the pump and 2 on the other side, one forward, one aft, down low- where's #5?

Re: purging water from the 496 cooling system
 

I still run AF through the system too. I use the method mentioned above early and late season when I am still using the boat but the temp may drop below freezing for SHORT periods.

Re: purging water from the 496 cooling system
 

Ditto.

Re: purging water from the 496 cooling system
 

I don't remember off the top of my head, but I am almost positive there are 5.
I may very well be wrong. Perhaps Dave M can check. My boat is put away.

www.mercruiserparts.com

BTT any new info on this?
Ill be winterizing my new to me 496 twin this year.

Wayne, there are I think two blue plugs on the OB side of the engine you will never reach. Purge as described, then pour in some RV antfreeze from somewhere to help with any remaining water- do this AFTER you verify the purge valves have closed- if I remember, they can stick in the open position- we've got at least 6 more weeks of boating to go-

Even though the heat exchanger is supposed to self drain when the valves are opened some have reported freeze damage regardless. Flush with anti freeze or blow out this item to be safe. $800/unit!

Im just preparing for later. Im not gonna be winterizing it yet. Ill be boating til at least the last week of October. Then itll be time to put it away for a few months. Should get her back out around Mid March.

BTT
Did the airpump deal and per the recommendation from a local merc mechanic pulled the blue plugs on the cool fuel and raw water pump.
Question is...
How many Blue plugs are there and where are they located?

Exactly how do you get the antifreeze from its container to the ear muffs?

With one of these:

http://www.westmarine.com/webapp/wcs...10001/8200/0/0

This unit then is hooked up to a set of flushing ear muffs attached to the lower unit water pick up and the jug placed higher than the engine so that the antifreeze is gravity feed to the engine's cooling water cavities? Is that how this goes?

I assume that you put duck tape or similar over the low water pickup?

Yes, you can do it that way.

However, its my personal opinion that muffs SUCK. One little slip or hickup and you have now burned up an impeller with even more hassle to go through.

I highly recommend a open T-fitting installed before the SWP; essentially a fresh-water-flush system. I have posted how and what parts to do this with, a few times here on OSO. It can be found with a search. Basically, you will need an open T-fitting, a 90* elbow with a barb on one end and theads into the T-fitting on the other, a hose, and way to hook up a garden hose AND positively seal the garden hose end when not hooked to a hose.

Also, when using the self-winterize kit, you can ensure that you induce positive flow of antifreeze by pressurizing the jug. See this thread on how to do so:
http://www.offshoreonly.com/forums/s...ight=jug+valve

(PS, you can also convert an old garden sprayer into a drive oil changer, and pressurize it like above referenced.)

Thanks for the explaination.

By the way I adopted your lawn pressure sprayer idea for drive lube change. I works great. Anything I can do to avoid getting that RedLine Shock Proof gear lube on everything I appreciate. I just wish the Bravo drain plug was not so hard to get to with the threaded hose fitting for the suction line when I pump it out. What a mess.

Four blue plugs(is all i could find and I looked for a while)....two by the water pump on stb side. On the port side there is one on the front of the side that is pretty easy to see. The other is near the back corner of the engine, on the bottom more than the others. I had to lay on top of the engine and lean over the sides to see and be able to reach it. Thats the one that quite a bit of water came out of, even after pumping. Not much came out of the others.