Winterizing Mercruiser 5.7 - draining all the water
This has been keeping me up at night, so I'm hoping somebody here can
shed some light:I removed the drain plugs from both exhaust manifolds & from each side
of the block. Then, I removed all six hoses from the thermostat housing
& flushed each with freshwater. When I tried to flush the large hose on
the port side (looks like it goes into the water pump), it filled up &
nothing came out of any of the drain plugs in the engine. So, I'm
assuming that one leads to the water intake in the outdrive, but
because the boat is in the water, I couldn't see anything coming out. I replaced all the drain plugs & filled everything with antifreeze
(removed the thermostat housing too, and added some directly to the
block, just for good measure), but I'm a little concerned about that
port-side hose. I pumped all the water out of there I could, and
refilled with antifreeze, but I'm worried there's water trapped
downstream of that hose that might cause problems. Any input or advice?
|
kevin
Dec 13
2005
|
| Kevin, You didn't say if the boat was in or out of water. If out of water the
best procedure IMO is to start the engine on the hose w/earmuffs on and
run it up to temp so t-stat opens. Dump in fuel stabilizer previously
so it circulates through the fuel system into the carb/throttle body. Once at op temperature shut off engine and water & pull all drains. My
1999 5.7 Merc has 5 - two on the block, two on the manifolds, and one
on the low point of the fat circ pump hose. Then stick a funnel in a
short section of hose to the earmuffs and ready 3 gallons of marine/RV
antifreeze. Have helper start pouring antifreeze into funnel and start
the engine. By the time 2 gallons have been poured the cooling system
should be pretty much full and by the 3rd gallon red antifreeze will by
pissing out the exhaust. At this point blast the fogging spray into the carb throat (remove
spark arrestor) until the engine dies. Some like to use Mystery Oil for
this. At this point the antifreeze has displaced any residual water in
the block and the fogging spray has protected the cylinders from
corrosion. This method was shown to me by a marine tech and has worked quite well
for the six seasons we've had our boat. There are other ways to
accomplish the same thing, but the important thing is to get any water
out of the block to prevent freezing damage and protect the combustion
chambers from corrosion. Wooly |
kingfish
Dec 14
|
| The drains on either side of the block are the low point drains for the
block. If you push the large water pump hose down, you might get another
pint out. When you close the drains and put anti freeze into the big hose,
it will fill the engine and come out the hoses that were disconnected from
the top of the Tstat housing. The input from the stern drive comes from the
top of the mounting bracket then goes to an oil cooler which is low on the
side of the engine. Which side I don't remember. Then it goes to the Tstat
housing. Your service manual should show you how the engine is plumbed. I
can't tell from your description which hoses you are talking about. If you
leave the boat in the water, you may not be able to prevent water from
reentering the engine unless you disconnect the input to the oil cooler and
raise it above the waterline and plug it.
"kevin c smith" <thesmith@gmail.com> wrote in message |
JIMinFL
Dec 14
|
| Okay, thanks for the info. I think I might just buy a heater for the engine compartment to keep my
sanity. |
kevin
Dec 13
|
| Yes, thats the line from the outboard pump. You can lower it as much as
possible to get water out of it. Because the water pump is a rubber
impeller is does not easily leak down. But it will eventually and if you
fill with antifreeze it will get into it. You did not mention but I'm guessing you are leaving it in salt water? Any
salt water in the lower unit will not freeze unless you are in the extreme
north. I suppose you have a reason not to pull it out and trailer it over the
winter. I/O's are not well suited to leaving in the water. They corode too
easily. "kevin c smith" <thesmith@gmail.com> wrote in message |
James
Dec 14
|
| Mine also has drain cocks on the sides of the block below the exhaust manifolds, right above the oil
pan.
--
John Herring Hope your Christmas is Spectacular!
....and your New Year even Better! |
John
Dec 13
|
| Try sticking a stiff wire up the drain openings to make sure all the water
drained from them. Sometimes (oftentimes) debris will clog the drains. |
Dec 13
|
| Often the drains get plugged up with rust and scale. You need to rod out the
passages behind the drain plugs.
JIMinFL
"kevin c smith" <thesmith@gmail.com> wrote in message |
JIMinFL
Dec 13
|
| So, you're thinking that hose drains into the block, like the one on
the starboard side? When I flushed the starboard one (and the block itself - under the
thermostat housing), water flowed freely out both block drains. |
kevin
Dec 13
|
| If water flowed freely out of all drains then they are not blocked. |
Dec 13
|
