350 MAG Freeze plugs

I have a 2006 Mercruiser 350 Mag with BIII drive. OW389906 engine #. My question is this. Where do the freeze plugs go that are hanging in a ziploc bag on the stering wheel. Just bought the boat and can only fine one empty hole and it is on the bottom front left of the motor in the front on a gray housing. I have felt everywhere I thought they may be. I felt on the bottom side of the manifolds and can't find a hole and can't see the sides of the block. Just wondering as my old boat (5.0 liter merc) was easy to find. It seems all the manifolds on this boar are piped down to the gray housing. Any pictures or diagrams around?

Not enough information as there are several options for that model and outdrive combo

look here and see what closest resembles your set up......cooling both closed and seawater cooling for Bravo


http://www.marineengine.com/parts/mercury_marine_parts/sn/OW389906

skinut1 said:

I have a 2006 Mercruiser 350 Mag with BIII drive. OW389906 engine #. My question is this. Where do the freeze plugs go that are hanging in a ziploc bag on the stering wheel. Just bought the boat and can only fine one empty hole and it is on the bottom front left of the motor in the front on a gray housing. I have felt everywhere I thought they may be. I felt on the bottom side of the manifolds and can't find a hole and can't see the sides of the block. Just wondering as my old boat (5.0 liter merc) was easy to find. It seems all the manifolds on this boar are piped down to the gray housing. Any pictures or diagrams around?

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Ayuh,.... Hook up the muffs, 'n fire it up,...

The holes for the drain plugs oughta become Obvious quite quickly,...

^^^ Lol, I love that answer, it never gets old Bondo.

In this case I'm thinking it may be better to install them in the correct position first as one is used for venting and the other two may suck in some air.

One blue plug should go into the thermostat housing port side and the other two will go into the sea water pump housing. Very hard to see and even harder to reach to install. Good luck.

Thanks Guys for the help. Another beer or two and I was about to do the fire it up and see where the water comes from idea.

you dont list how many plugs so try the therm housing, the large hose from therm to wp , raw water pump drain plugs, a variety of places also depemnds on what type of cooling system and drive.http://www.marineengine.com/parts/mercury_marine_parts/sn/OW389906

I have 4 plugs and a clip. I know the metal clip hooks the large inlet hose from the outdrive back together. I know one plug goes in the bottom of the water distribution housing at the front bottom left side of the motor. I know one plug goes into the housing by the thermostat. That leaves 2 plugs. I assume they go into each side of the block. But I can't find a diagram showing where. My ribs are sore from laying in there and feeling around. It is a raw water cooled engine /BIII drive.
One drawing showed plugs in the elbow that comes from the bottom of the manifolds. Mine does not elbow, it just goes down and to the water dist. housing. I work on tractors, trackhoes and everything else thats broke but this has me confused.

what type of cooling system and what kind of drive?

boat_tech said:

and the other two will go into the sea water pump housing. Very hard to see and even harder to reach to install. Good luck.

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skinut1 said:

That leaves 2 plugs. But I can't find a diagram showing where.

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2 of item number 10's go into number 8, http://www.marineengine.com/parts/mercury_marine_parts/sn/0W389906/44420H7TT/11681_320

I finally hooked up the muffs and turned on the water and found the holes. They were where boat tech said but my gosh they are impossible to find even with water squirting out. You have to use two fingertips to screw them in. Got it done and thanks for all the help to everyone.

I am going to put it in the lake tomorrow and then on the lift. I guess if I remove the four plugs and the hose, it will be ok if the temp gets down to 25 or so next week for one night?