Exhaust Riser

[Ken Juul]

Mine broke on Monday.  We were stuck in St Augustine, FL until this morning.  Not a bad place to be stuck....but drained the cruising kitty a bunch.  We got a new stainless one from the factory.  Easy install.  Currently in Daytona Beach.  From a couple of the reply's I've gotten from the blog, it seems like  13-14 years is what you can expect from the original factory install.  If you are getting close in age it might be wise to just change it rather than have it break at an inopportune time.

[karista]

Ken
You are very much on the mark, I also have a 1990 model and my heat riser failed about 2 years ago. I also got one from the factory, the weld just broke the nipple off.
I have followed your blog as we did the same trip a few years ago from Deale, MD, we had no problems with the boat during the entire trip, sailed down and then crossed over to the Gulf and then up to St. Petersburg.
You will have a great time going down to the Keys, the Heat Riser install is not difficult, hopefully you installed the new Silicone Hump hose at the same time.

Bernd

[Kevin Henderson]

I'm curious...

I have no indications of an exhasut riser failure and I also recently added the silicone hump hose.  Are there any good specific inspection clues that a person can see to determine if it's time to replace? 
What are the clues to a deteriorating exhaust riser so that one can take action before it's desperate?   

[Stu Jackson]

1.  Are there any good specific inspection clues that a person can see to determine if it's time to replace?  

2.  What are the clues to a deteriorating exhaust riser so that one can take action before it's desperate?  

Kevin,

1.  Nope, not really.  You'd have to remove the insulation in at least two or three places.  A friend with a C310, Paul J, who also posts here, recently posted a picture of his covered with JBweld!  If you peel off the insulation at the nipple and just "above" it (closer to the engine) you can see if there's any signs of the joints/welds starting to go, i.e., rust, water!, etc.  I don't know of anybody who does this, although some might.

2.  Clues?  Black/brown smoke when the engine is running, a horrible smell and salt water all over is what happens when it breaks.

Either order a new one as a backup NOW as well as a gasket(s) for the manifold connection and have it ready to go, or wait until one gets delivered when, not if, yours goes.  I'm doing just that this month or next.

It's a preventative maintenance item that "usually" can't be partially repaired to limp your way home, I sailed a one hour trip in 4 hours against current when mine cracked.  

[Ron Hill]

Guys : I agree with Stu.  It is difficult to peal back the insulation wrap to inspect the welds at the curves.

The most frequent riser failure is the weld at the nipple where exhaust water enters.  As I mentioned numerous times before :
1. Get rid of the wire reinforced hose that goes from the anti syphon valve to that nipple.  Replace it with 5/8" nylon reinforced hose so all the engine vibration is not transmitted to the nipple weld.  Then when you get a new riser make sure that nipple is "stake" welded on the inside.
2. Carry some muffler patch onboard for emergency repairs.
3. Get the Trident hump hose from the riser to the inlet of the muffler. It takes up some of the engine vibration that is transmitted to the fiberglass inlet hose as well as the welded joints of the stainless riser itself!!

A few thoughts

[Indian Falls]

Ron please explain:  What is stake welded?  I can't find any info that pertains to this application. 

Thanks!

Dan

[Ron Hill]

Dan : A "stake weld" is a single bead usually used to hold pieces together before a continuous weld is made.
In the case of the riser nipple the continuous weld is on the outside and the "stake weld" is that extra bead of strength on the inside of the riser (because you can't get a continuous weld on the inside)