HELP! Metal/rubber in lower unit

[jsw102503]

I'm headed out this morning and saw metal/rubber behind my prop. See the attached photos. It is a used boat but i'v had it a year. Any ideas what this stuff is? Is it safe to go out once I removed it?

Thanks in advance!

 

[achris]

How about some engine and drive information?

Looks like a piece of exhaust shutter. But need more info to be sure.

Chris...

 

[jsw102503]

Sorry. In my rush I forgot the engine info. It's a 4.3L Mercruiser. Carb. I'm beginning to think it's half of an exhaust shutter. Do you think I can run it for a few hours today or is this something that would be really bad? Not sure where the other half is.

 

[achris]

Merc have been using the 4.3 since 1984. During that time the exhaust system has seen many changes. At least a year would be useful...

Yes it looks like half the shutter. 2 questions spring forth. 1 where's the other half? 2. Why did it 'fall' off?

Run without it? I wouldn't... Too much risk of flooding the exhaust manifold with sea water, then into the engine, likely bending a rod, or worse...

But, it's 4th of July and you may consider a high risk of having to replace/seriously repair the engine worth it. Up to you.. As I said, I wouldn't... It's just a day, like any other...

Chris

 

[jsw102503]

Thanks. I definitely won't take it out.

It is a 2003.

We were trying to go today to avoid the 4th of July crowds. We like the lake quiet and un crowded. I guess I have a project now. Thanks for the advice!

 

[Rick Stephens]

When you purchase the shutters, also purchase riser to manifold gaskets. Only use Mercruiser OEM metal gaskets there. Aftermarket paper ones don't last. That will make your repair very easy and only take a couple hours.

 

[achris]

2003 means the latest design. I have an article in the sickies on those shutters. You'll get the part numbers you need from it too.

No need to pull the exhaust elbows off. Just loosen the 4 clamps on the rubber sleeve on the top of the y-pipe and slip it down. Then loosen the 2 clamps holding the aluminium elbow to the rubber sleeve on the aft end of the exhaust elbow. Simply remove the aluminium elbow and that gives you access to the top of the y-pipe to fit the new shutters.(and do both sides).

I'd also be pulling the drive and making sure there isn't a piece of shutter lodged somewhere where it can do damage..

Chris...

 

[Rick Stephens]

2003 means the latest design. I have an article in the sickies on those shutters. You'll get the part numbers you need from it too.

No need to pull the exhaust elbows off. Just loosen the 4 clamps on the rubber sleeve on the top of the y-pipe and slip it down. Then loosen the 2 clamps holding the aluminium elbow to the rubber sleeve on the aft end of the exhaust elbow. Simply remove the aluminium elbow and that gives you access to the top of the y-pipe to fit the new shutters.(and do both sides).

Chris...

Yer a better man than I. I've never been able to slide mine down.

 

[achris]

Yer a better man than I. I've never been able to slide mine down.

:noidea: I've never had a problem.

Cheers.

 

[jsw102503]

Well that's a twist I didn't see coming.

The piece that was caught behind my prop was definitely a piece of a exhaust flapper. To inspect the flappers I had to cut the exhaust tube but I checked the port side and it looked great. The starboard side was a real pain because of the walkthrough transom. But the starboard side looked... great.

So a flapper was caught in the exhaust. I have owned the boat for 1.5 years. Apparently a previous owner had the flappers replaced but neglected to find the pieces that went down into the exhaust.

Boat is running well and has two functioning flappers. Do I run as is or should I start looking for other items that may, or may not, by caught in the exhaust?

 

[Rick Stephens]

Pull the outdrive and take a peek up the exhaust passageway. Common issue is that the shutter
pin drops down and sits at the bottom of the Y pipe and then wears a hole in the Y pipe. That then lets water into the bilge.

If you haven't already, assume the previous owner did no maintenance at all and go through the service manual and check everything. You should pull the sterndrive off every year, change oil, inspect U-joints, bellows, gimbal bearing and alignmet before reinstalling.

 

[jsw102503]

Alright. Thanks for the suggestion Rick. I pulled the outdrive (a first for me) and it only took me about 2 hours by myself. Everything looked great. Clear with no damage or debris. Now I just have to order the exhaust tubes and re install.

Thanks again everyone.

 

[karayj]

achris
Moderator Is 100% correct I did mine last week easy job ... Use a 1/2 ratchet to tighten and loosen the claps.
Make sure you align the claps to make for easy tightening. NO need to when you put the replacement in Metal side up ...
Treat it like a PacMan going downwards <<<<< .