Do I have an exhaust water leak?

[Ron Hill]

Paul : Look in the old Mainsheet tech note and you'll find 3 articles
1. Hump hose
2. Removing/replacing the exhaust riser
3. Replacing the muffler

You never did mention where the "black water" leak was coming from.
Just curious - before you start throwing parts at the problem!!

A thought

[britinusa]

Ron,
right now I'm baffled about the origin of the black water and I'm only guessing that it's from the Muffler.

I've not found any mention in the forum about bilge water with black particulate as yet. But I'm still looking.

The Aqua lift muffler does show signs of weeping around the inlet hose. I'll know better when I get that hose off.

I think that the black particulate may be exhaust particles, hence why I'm focusing on the exhaust system. There was no sign of running water when I ran the engine and viewed it from beneath the aft berth.

It's nice to know that repairing the Muffler is not rocket science.

Paul

[Stu Jackson]

Some have used red RTV on the exh gasket.  Not saying that's a good or bad idea, but if you do, make sure you don't  ooze any  into the water ports on the manifold.

kk

From my linked Tech Note (2016) Muffler Replacement, for those who, for some bizarre reason, don't read the posted links:

Flange Gasket: We carefully cleaned both the end of the exhaust manifold and the flange. This is essential. We used a bit of high temperature RTV gasket material on the flange side of the gasket. This made it easier to deal with the gasket while we aligned the flange and the studs, since the gasket was stuck right on the flange with the RTV. Don't be tempted to slather RTV on the manifold end. First, it isn't necessary if the manifold is perfectly CLEAN, and second, it makes cleaning the manifold end much, much harder the next time, and there will be one.

[KWKloeber]

Did you get a chance to ck the vent hose yet?  Could be dumping the junk into the bilge.   There is a foam filter block under the valve cover, but if yours is routed to the air intake, that's moot.

 

[Ron Hill]

Paul : If the black water doesn't have any oil in it forget the crank case vent.

From what you've said I'll guess that at some time your engine had a hi temp problem caused by lack of raw water.  Then what happens is the hot exhaust (not cooled with HX water) deforms the round fiberglass inlet to the muffler.  Once deformed it's impossible to have the hose clamp seal that wire reinforced (very stiff) black hose.

Here's a suggestion: Cut off the old black chunk of wire reinforced hose and then you said you were going to get a hump hose. With the old hose off, inspect that inlet and make sure that it is round.  If not try some Marinetex or epoxy paste to fill in any deformed groves - making sure that you don't increase the inlet diameter.  You just want to make it round so a hose clamp will seal (I double clamp mine). 
Then install the hump hose without removing the exhaust riser. Just put some soap on the inside of the hump hose so it slides in place.

Also make sure that the 5/8"? hose from the anti-siphon with the HX water to the nipple in the exhaust riser is NOT wire reinforced.  It only need be nylon reinforced.  That stiff wire hose puts undo engine vibrations and strain on that nipple weld causing it to crack!! 

A few thoughts 

[KWKloeber]

Paul

Ron's suggestion on the inlet - reminds me.  The 1st time I repaired my leaking muffler the inlet/outlets were "ok" but I could see that they could become a problem.  I had a pc of thin aluminum tubing laying around that was a close tolerance fit to the ID.  it may have been from a broken Sunfish spar (CRS) though that seems too heavy (from the little I can remember.) 

I tapped it down into place (tight enough fit so I didn't need any epoxy) and it strongly reinforced and kept them 'round'.  If you find the inlet squashed and can find a similar tube it would probably "re-round it" and also reinforce it.

k

[britinusa]

Ron, Ken,
thanks again.

both those ideas make sense.

The Hump is on order, but I'm going to head down to the boat either Tuesday or Definitely Wednesday and cut out the old inlet hose.

Will report on inspection.

Paul

[Stu Jackson]

............................but I'm going to head down to the boat either Tuesday or Definitely Wednesday and cut out the old inlet hose.

Will report on inspection.

Pictures, take and post them, please.  We always like to see how somebody else skins their knuckles!!!   

[britinusa]

Update.
1st! Thanks everyone!
Because of the support on this site and the volumes of experience from other owners, this job so far has been a doddle!

Step 1: Remove the hose from the Exhaust riser to the Muffer and Inspect the hose and muffler / exhaust connections.
This was really easy!

I opened the head cupboard door and taped it open to the head doorway.
Next: disconnect the hot and cold water hoses from the head sink faucet
Next: disconnect the raw water hose from the sea water strainer
Move all those hoses out of the way.

Next I removed the 4 clamps on the Muffler Inlet hose.

I used my dremel to cut a vertical slit in the middle of the tube on the outboard side of the short hose, piercing the hose. Then extended the slit up to the to of the hose being careful to just cut through the steel reinforcing wire. As I did so the tube stated to split open wider and wider. I was able to dremel my way through the top of the hose but could not get all the way down to the muffler without risk of cutting into the muffler fiber glass. So I used a sharp knife to cut through the remaining hose and the whole hose came out easily.

Now I cleaned up the muffler to inspect it. Definitely signs of cracks around the hose connection. So I removed the outlet hose too. No cutting this time.
I removed the two hose clamps on the outlet hose then pried up the lower edge of the hose with a large flathead screw driver, then with both hands inside the cupboard I was able to twist the hose back and forth and disconnect it from the muffler.

Cleaned up the outlet connection. Same thing, signs of cracks around the connections where the are attached to the muffler.

In both cased, the inlet and outlet tubes, the cracks were minor. So I elected to seal and reinforce them with marine epoxy.
After using a wire brush to clean the area around the tubes and then sand paper to roughen the surface and a clean up. I applied about 1/4" rod of the epoxy putty and forced into the area that I thought were cracks.

It's setting now, (that was two hours ago, so it should be steel hard by now)

And now I have two questions.
#1 What is the best thing to put on the new hump hose to make sure that it's easy to take off in the future without cutting it.

#2 And this one is my main concern. Do I need to adjust my exhaust riser?


I hope that you can see that the exhaust riser tube and the muffler tube are not even close to being parallel. Can/Should I correct that by rotating the riser?

The new hump hose has arrived, definitely more flexible than the old black exhaust tubing, but I think I'm going to have to cut it down from the 8.5" delivered size to something more like 6". I'm anticipating putting the top end in place first and then bending the hump hose to attach it to the muffler tube.

Thanks. More pics being uploaded to my Blog.

Paul

[KWKloeber]

C'mon Paul, not even one skinned knuckle?  Surely there must be a blood picture coming?

Pics didn't load up?

k

[britinusa]

I did get grimy under my manicure!

[britinusa]

Cutting out the Inlet Hose

[britinusa]

Ugly Nipple end of Riser

[britinusa]

The Inlet Hose Connection on the Muffler

[Ron Hill]

Paul : Looks good!! 
I'd put the hump hose on the muffler first and then bend it down to fit it onto the riser.  Like I mentioned before, I'd put some dishwashing soap on the inside and maybe even coat the muffler inlet and the riser - so it slides on easily. 
Don't get the soap on the outside of the hump hose or you'll be working with a "greased pig"!!

Looking at the distance, I'd cut the hump hose to 6 3/4" to get the max overlap.  You can always cut it shorter if need be!!

Don't know what you mean by "adjust the exhaust riser"??  The hump hose is bendable enough to take any lateral play needed.

A few thoughts