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Raw water engine winterize

J

jeffnoank

Member
I have a 7.4mpi in my boat which I just hauled for the winter. This is my first season and I need to winterize it. Being that this a a raw water cooled engine I realize I can't just run pink antifreeze through it. I was told I need to drain the engine first and then pour antifreeze into some hoese, my questions are.

Where are the plugs / drains located to drain the water from the engine ?

Once drained which hoses do I need to remove to pour antifeeze into ?

Any and all info would be appreciated, any diagrams or links would be helpfull.
 
what year and make? merc volvo

some mercs you can go to there website and download a user manual for free that tells you all needed maint and how to do it.
 
Last edited:
It's a mercrusier, 1998

I was just reading a site online which said another option is to remove the theromstat and then run the antifreeze through the engine , with therom out antifreeze can reach all areeas.

Make sense ?
 
Your engine requires a specific fuel/2 cycle oil mixture for the injectors for storage; don't remember the blend ratio.
 
You do not need anti freeze in the engine, just drain it thoroughly. Ditto the drive.
If you have drain cocks in the side of the engine block it makes it easier. Otherwise remove the drain plugs, loosen the large hose from the water pump and get as much water out as you can. If you have oil coolers, undo the water hoses and shake out the water from the cooler and the hoses. Anywhere the water can be trapped like hose bends, should be undone to let the water out. Reconnect everything as you do this so you don't inadvertently stat up in the springtime with loose hoses. Spray your hose clamp screws with Boeshield or similar.
Seems a little early to be taking the boat out of the water in September.
 
I pull the plugs from the block and the exhaust manifolds to drain. Then, I either pull the thermostat housing or the hoses and start pouring pink antifreeze until it starts coming out the block drains. I replace the plugs and continue pouring antifreeze until it starts coming out the manifolds. I replace the manifold plugs and then continue to pour antifreeze until it comes out the drive. This way, you are always sure antifreeze gets to where it needs to go and displaces or mixes with any water that could be trapped. You may not need antifreeze but $10 or $12 for piece of mind sure beats $2000 or $3000 for a new motor.
 
tried to copy out of the merc manual.

I don't use the oil mix just sta-bil marine, use fogging oil instead and add antifreeze with corrosion inhibitor.
I have a MPI with the single point drain system.

NOTE: Use this procedure if your engine is not equipped with an air actuated single point
drain system or if the single point drain system fails.
1. Remove three blue drain plugs: One from the distribution housing (lower front, port side)
and two from the seawater pickup pump (front, starboard side).
77917 77908
a
a
a - Blue Drain Plug
2. Verify that water is draining from each opening.
3. Allow the system to drain for a minimum of 5 minutes. Mercury MerCruiser recommends
leaving the plugs out while transporting the boat or while performing other maintenance
to ensure that all water is drained.
4. Crank engine over slightly with starter motor to purge any water trapped in seawater
pickup pump. Do NOT allow engine to start.
5. Prior to launching boat or starting the engine, close the drain system by re-installing the
three blue drain plugs.
All Models
1. For additional assurance against freezing and corrosion, fill the cooling system with a
mixture of propylene glycol antifreeze and tap water mixed to manufacturer’s
recommendation to protect engine to the lowest temperature to which it will be exposed
during cold weather or extended storage.
a. Remove thermostat housing or hose and fill with propylene glycol coolant until
engine block is full. If thermostat housing was removed,


1. In a 23 l (6 U.S. gal.) remote fuel tank mix:
a. 19 l (5 U.S. gal) regular unleaded 87 octane (90 RON) gasoline
b. 1.89 l (2 U.S. qts.) Premium Plus 2-Cycle TC-W3 Outboard Oil
c. 150ml (5 ounces) Fuel System Treatment and Stabilizer or 30 ml (1 ounce) Fuel System
Treatment and Stabilizer Concentrate.
Description Where Used Part Number
Mercury Fuel System Treatment
and Stabilizer
Fuel System 92-802875A1
Mercury Fuel System Treatment
and Stabilizer Concentrate
Fuel System 92-802876A1
Premium Plus 2-Cycle TC-W3
Outboard Oil
Fuel System 92-802824A1
2. Allow the engine to cool down.
3. Activate the Schrader valve to relieve fuel pressure.
4. Close the fuel shut-off valve, if equipped. Disconnect and plug the fuel inlet fitting if not
equipped with a fuel shut-off valve.
5. Connect the remote fuel tank (with the fogging mixture) to the fuel inlet fitting.
IMPORTANT: Supply cooling water to the engine.
6. Start and operate the engine at 1300 rpm for 5 minutes.
7. After specified operating time is complete, slowly return throttle to idle rpm and shut
engine off.
IMPORTANT: Ensure that some fogging mixture remains in the engine. Do NOT allow
the engine’s fuel system to become completely dry.
8. Remove and discard the water separating fuel filter.
9. Install a new filter.
 
capnlazy said:
Of course you want to do the fuel system procedure before the cooling system.
Click to expand...

some people heat up the engine,shut it down then drain it, have there own oil concoction mixed in the fuel/water separating filter, screw that in,start engine and add antifreeze via muffs thru water intake in drive. its all what you like to do and are comfortable with.
 
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