Mercruiser exhaust flappers

[Darol Wester]

We have a 78 Cruiser w/260 Mercruiser. We had the out drive off for lubing and such and we found three of the four exhaust flappers just inside the port where it comes apart. That leaves one in there somewhere??? Can these things after coming loose lodge themselves in a way that will cause you grief? We've looked but no sign of the last one.

What's the best way to retrieve it. Also, does anyone know where I can get a diagram on where the flappers originally are in the exhaust system? Thanks.

 

[Laddies]

Re: Mercruiser exhaust flappers

They were original in the top of the exhaust horns, you will have to remove the elbows and the short exhaust hoses to replace them

 

[lrlima]

Re: Mercruiser exhaust flappers

for diagrams, check Dougrussell.com. Go to the parts section and you can search by year, engine type, etc.

 

[Darol Wester]

Re: Mercruiser exhaust flappers

These flappers came out in what looks like broken halves. Similar to two small shoe heels. Do the new ones come in one piece and these just broke in half before they fell out? The diagram seems to show it as one piece. It appears that they pivot like a damper in the pipe of a wood stove. Just trying to get an idea how they work.

 

[Laddies]

Re: Mercruiser exhaust flappers

The flapper pieces you have are the ends of the flappers the center is still in the horn take a look at the parts diagram

 

[Bondo]

Re: Mercruiser exhaust flappers

It appears that they pivot like a damper in the pipe of a wood stove.

Nope,........... More like a Duck flapping it's Bill.......

 

[Darol Wester]

Re: Mercruiser exhaust flappers

I have the picture in my mind. Thanks guys. I appreciate the info. It's always nice to know what to expect going into a new area.

 

[Don S]

Re: Mercruiser exhaust flappers

I hate to be the one to rain on your parade guys, but the exhaust shutters on the 78's were in the bottom of the exhaust Y, under the engine.

Look at This drawing and look at part 21. It bolts directly to the bottom of the transom shield.
It wasn't till the mid 80's (I think) that the shutters were moved up to the top of the exhaust Y's.

PS: Item 19 is the shutters (aka Flappers) and there is a set on each side. Pictures is a bit fuzzy.

 

[Darol Wester]

Re: Mercruiser exhaust flappers

So does this mean that I have to remove the engine to replace the flappers?

 

[Bondo]

Re: Mercruiser exhaust flappers

Ayuh,.........

I Really Doubt you can get a wrench on those 5 bolts at the transom......