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.