Mercruiser 165 L6, Do I need bellows adhesive on the upper bellows?

[ttownthomas]

I am going through my 165 mercruisers (Chevy 250 L6, 4.1L). The manifolds and risers were rotted so I replaced them along with all the gaskets. Both shutters were missing so I am replacing those. The upper bellows are leaking around where they attach to the exhaust elbow. This is the bellows that is inside the transom. Its a rubber tube from the riser downpipe to the exhaust elbow. The rubber bellows were in very good shape so I did not replace them but the exhaust elbows are somewhat corroded. Unfortunately it does not look like the elbows can come out easily without pulling the motors. I assume this junction is leaking because I did not use any bellows adhesive and they cant seal because there is no-longer a smooth surface on the elbow due to the corrosion.

What I'm asking is should I be using bellows adhesive here (see photo)

 

[Bt Doctur]

Normally no adhesive is used there

 

[Bondo]

The rubber bellows were in very good shape so I did not replace them but the exhaust elbows are somewhat corroded. Unfortunately it does not look like the elbows can come out easily without pulling the motors. I assume this junction is leaking because I did not use any bellows adhesive and they cant seal because there is no-longer a smooth surface on the elbow due to the corrosion.

Ayuh,..... Welcome Aboard,....... I assume you did yer best to clean up the corrosion,..??

If the down-pipe is that rotten that it needs replacin',... Yes, the motor has to come out,......

I replaced a burnt out rubber coupler awhile ago,... The new ones are a Super tight fit,....
It seemed to be too small, but the part numbers, 'n serial numbers, 'n a trip into the parts racks confirmed I had the Right coupler,....
With a liberal amount of Quicksilver Perfect Tune, much force, 'n a few choice words, I got it in-place,......

Good Luck with yer's,......

I might try sealin' it up with some form-a-gasket 3#, or maybe #2,.....

It's a touchy spot, 'cause the outside water level is 'bout right at the top of the down-pipe,.....

 

[ttownthomas]

Yeah. gonna try to seal them up so I can run the boat and see what else it needs. Boat is new to me.

 

[ttownthomas]

So...my coupler slides right on and off. Perhaps more cleanup and new couplers would do the trick

 

[ttownthomas]

I felt the cast elbow was not too rotted. Picture below. I cut an 80 grit belt sander belt in half and turned it inside out and used it to clean up the elbow and then installed the brand new rubber coupler. The new coupler was VERY tight. I put a very thin coating of marine grease on it to get it to slide over. I hope that was not a bad idea. Also the coupler I removed had 2 clamps on the bottom and one on the top. Is that overkill? The top clamp seems like it is almost too high up to do any good.

Now that it is not gushing water I noticed that it has a very bad fuel leak. Looks to be coming right from the fuel pump. I guess Ill start another thread