Mercruiser Black scorpion question

so like most, I come to Wakeworld with questions:
I have a 2007 212 Supreme, with the black scorpion motor. Had the boat about a year, great boat for the money ( dealer repo )
Saturday, I was getting ready to hook it up to the Fake lake and let her run a bit, when I noticed this little plug sitting under the motor kinda close to the bilge pump. I only saw one other on the motor, on the port side front close to I think the water pump. I looked all over and couldn't find any other like this one.
I hooked the fake lake up and charged it with water and found no leaks anywhere on or near the engine. I called a friend of mine with the same motor, and he came over and couldn't find anymore plugs. I started the boat, and let it run for about 20 minutes, and never had any water leak from the motor, or in the engine compartment. the boat got to temp, and seemed just fine. My buddy said they take these plugs out when they winterize boats, which I have not done ( So Cal weather is great),in order to flush out the remaining water in the block.
My question is, does anyone know where I can find a schematic of the motor detailing where these plugs are on this motor? I looked on mercruiser a few minutes ago, and I think there are 5 of them. I went out to the boat and found three( the one on the front of the motor, and two on the headers). I want to be sure I am not missing one and if so I can re install this one.
My guess is whoever serviced this boat before I bought it, or maybe from the factory, they were taken out and this one was dropped. Instead of fishing it out, the mechanic maybe just grabbed another off the shelf and installed it and left this in the bottom of the boat. I really don't know, but after running it and everything is dry, that's the best I can think of. there's a couple tie straps, and a few stainless screws down there as well FWIW. Any thoughts, advice is greatly appreciated. thanks again in advance.

If you ran it for that long and found no streams coming out then I would say you are correct in you assumption of one dropped and replaced.

there should be eight plugs seven if you have a shower there is one on each manifold one on each side of the block two on the water pump one on the fuel cooler one on the trans cooler and one one the front of the engine think that is all of them make sure to clean all debris out of the bilge a zip tie or a screw can block the bilge pump it is most likely debri from the manufacture had the same stuff in mine

They are really easy to drop and if you have an extra one laying around, its much easier to replace it rather then trying to fish out the one you dropped.

I'm going to go with your hunch also. A mechanic will often drop something in the bilge, and it's much easier to grab another than fish around down there for the missing part.

Many brand new boats have "extra" parts lying around in the bilge.

Besides, if you were missing a plug, and you ran the engine, it would be shooting water out that unplugged hole.

Lucky to have an extra one. I always lose those suckers. That ones got the o-ring on it still so it's perfect.

As stated above, there are 8 of those to drain the water and if one was missing you'd have a lot of water coming out of the hole while it was running.

There are 2 on the raw water pump. 1 on each side of the block and 1 on the bottom of each exhaust manifold. One on the heat exchanger for the tranny and one at the circulation pump.

I have the same year and model Supreme w/Black Scorpion.Mine has 2 on the raw water pump,1 on each side of block,1 on each manifold,1 on the circulation pump hose,and the last 1 is on the fuel cooler hose.You have to get in the storage lockers to reach all of them on the 212.

(Message edited by wakebrdjay on February 15, 2010)

Direct from Mercury. Total of 8.

awesome, thanks guys. I'll check these spots when I get home. I feel better knowing that if one was actually missing, I'd have water shooting into the engine compartment, which is not happening.

Don't overtighten the plugs when replacing them, I broke a couple of them and had to extract them out. This happen to anyone else? Maybe just me........$2.99 a piece at the dealer

x2 on the don't overtighten,the end will break off causing it to leak.The center of the thread part is hollow.

some have 6,7,8, or 9

if you post serial number i will post the manuals pics

model#3-3500341
serial# 0W690450

thanks

free manual here!!!

http://www.4shared.com/file/119353633/70c4dde5/Mercruiser_Service_Manual_31.html

you got 7

2 blocks
2 manifolds
2 water pump
1 fuel cooler

Thanks Justintime.
one last question. It's a 2007 boat, I bought as a dealer repo in 2009. I've only got about 40 hours on the boat, when should I replace the water pump impeller? I heard every two years, but with low hours, does that still apply? thanks

Marc,I would check for a plug on the water circulating pump hose also.My Black scorp. serial# is 0W695032,It has 8 plugs,pretty sure serial#s 0W690000 and up have 8 plugs. http://www.ishopmarine.com/ishop/jsp/AsplIsmCcatViewBase.jsp?&lvlCode=4&pCode=C0010053& path=MC~A0000010~M0000602~M0000604~C0010053&isFrom CMS=false&hideAdd2CartButton=&isStandAlone=&is4Cms Shop=&reqln=Unknown&reqem=Unknown&reqph=Unknown&re qFor=29&req4Browse=1&docId=&docName=&isForSupStore =true&cCatFilter=MC&eCatSupFldr=supplier-300-020-MC Exploded view of cooling system

Water impeller should be changed at 100hrs or yearly

yes they can last 10 years, seen it

that manual i sent you and the owners manual's have the schedule in them

follow it to the T