Mystery plate & rubber seal in outdrive and burnt water tube.

[wat50]

I decided replace my impeller on a 1998 mercruiser alpha 1 gen 2 for the first time since I have owned the boat. As soon as I wiggled the outdrive loose this random metal plate hit the floor and I cant figure out where it went. I contacted a local boat mechanic and he said that he thought it might have something to do with the exhaust keeping water from flowing back into the engine, but it didn't belong in the outdrive. Looking through the entire sterndrive and engine schematics I still cant find it.
Also my water tube was completely burned. The inside was still intact as was all the o-rings so I believe it was still functioning as it should unless my temp gauge doesn't work. The impeller itself was good. But if you look there is a piece of black rubber that' not apart of the white guide tube that is also a mystery piece to me. With the tube good I was just going to reinstall without the guide tube unless that would be a problem?
Information with these three things will be extremely helpful.

 

[JASinIL2006]

The metal half-disk is what remains of your exhaust shutters, which keep water from backing up your exhaust into the engine. Did you have a problem with the boat overheating at some point! They often burn up the rubber pieces on the shutter and cause them to fall out.

 

[Scott Danforth]

get a complete water pump kit with the amount of damage you have.

also, you will need new flappers and most likely new exhaust hoses because that motor most likely has suffered a complete loss of cooling water at some point.

 

[GA_Boater]

I think the melted plastic wrapped around the water tube is the water pocket cover.

Fair warning - I know nothing about Mercruiser outdrives, just read threads a lot.

 

[rickasbury]

Your getting solid advice.

 

[wat50]

That's exactly what it is! Man I have been pulling my hair out all day. Thanks a ton. And installing new flaps looks like a pretty quick job. I've only owned the boat for 5 years and been on the water about 20 times, I've never had a problem with it over heating. It always stays around 140. I went ahead and put my outdrive back on and cranked it on the muffs. It spit water its normal amount (normal for my ownership of it). Hopefully the other half of the shutter is still in place and will stay until I get a new one in. I'm thinking it will be alright to drive a little bit until then?

 

[wat50]

I even looked at this today and didn't put it together.

 

[nola mike]

Who knows how long it's been like that. Don't make any abrupt stops. Those flappers are what keep water from backing up into your engine.