Wet Exhaust Hose Failure

[wings&wheels]

Restoring an older Century Resorter inboard utility and did a final run up on a hose after I put her all back together. She ran great but I noticed that I wasn't getting as much water flowing out of one exhaust, but was pushing out more steam, and that riser was hotter than the other. Hoses seemed fine from the outside, but a friend (who knows more than I ever will about boats) suggested that I pull the hoses and look for this...delamination of the inner hose liner restricting the exhaust and causing water to pool and boil. Never seen anything like this before.

Basically, this is an aortic dissection of the hose.... Short term solution is a high heat fiberglass coupler splice, well above the water line, and a few feet of new hose. Winter solution will be two new hoses.

Pic is looking upstream, towards the engine.

 

[BrocLuno]

Gates Green Stripe. Worked in marine engineering for many years. Seen a few like this. Not common, but happens.

 

[Linctex]

I think silicone hoses (colored, like "intercooler" hoses) would be best

 

[UncleDave]

I see this all the time on high powered I/O 's and inboards.

Hardcore guys shun the hose coupler and go for a completely welded setup.

UD

 

[wings&wheels]

Thanks all.

The coupler and short run of new hose is so I get her in the water at least once this year, w/ a long term repair over the cold season. I am thinking of a way to run a more durable solution for the first few feet out of the risers, but that may require new risers w/ angled outlets.

 

[BigCahuna]

Make sure your water pump is doing something. Just steam coming out doesn't sound like it's moving much water. Hot exhaust gas will melt that hose shortly.,,,

 

[Donald]

I would pull the riser. Also the Mercruiser had a shutter in the exhaust to prevent the water from being pushed up backwards towards the engine.

 

[wings&wheels]

Thanks all. The riser appeared clear, but did have some internal corrosion so I will be replacing them over the Winter, probably with the 15dg ones so I have less of a curve in the hose just aft of the riser.

I'll launch her in a week or so, get some low power cruising shakedown cruising and finish the exhaust over the Winter.

 

[RTexasF]

Pictures please when you splash that old gem.

 

[wings&wheels]

Originally Posted by RTexasF
Pictures please when you splash that old gem.


RTexasF, we have a crazy few weeks so it may be a bit, but here are a few pics from the barn:


She is an early 'glass Resorter...I will own a wood boat when I am completely retired.

 

[wings&wheels]

...and Complete!

Dropped the engine box in and ready for water.

(can' figure out how to rotate pic...fine on y pc)

 

[another Todd]

Originally Posted by wings&wheels
Thanks all. The riser appeared clear, but did have some internal corrosion so I will be replacing them over the Winter, probably with the 15dg ones so I have less of a curve in the hose just aft of the riser.

I'll launch her in a week or so, get some low power cruising shakedown cruising and finish the exhaust over the Winter.


They always have corrosion, the important thing is that they are clear and easily flow water. Don't use a powered wire wheel to clean the mounting surfaces either, gently scrape only.

 

[wings&wheels]

Thanks for the scraping tip another Todd. The quick wire brush is always tempting.

 

[wings&wheels]

Launched her and she runs great, fast and loads of fun, but the port riser runs noticeably warmer then the other. Not excessive, but warmer so we will use her for the next month or so and I have a project for the cold season.

Interesting that her speed at idle is 7+mph with a significant wake so we'll be in and out of gear a lot in the long no wake zone to the house. Something to get used to.

My Bride snapped this long distance pic as I navigated the narrow canal.

Thanks for the tips all!

 

[DoubleWasp]

Seen it many times. Might be worth reviewing your impeller and the suction tract for your raw water. When water flow begins to go down, water can take the path of least resistance.

Also remove the caps off of the bottom of the manifolds. Even in fresh water, manifolds take on a black silt that clog them. Genuine Mercruiser/Quicksilver manifolds have screw-in plugs at the bottom of the manifolds. Take them out and you might be surprised. I've seen the black silt get so bad that they busted the manifolds apart like ice when they dried.

Manifold resistance many times is the cause of hot risers. I've seen too many engines get new risers on top of new manifolds just to have the same hot running issues.

 

[wings&wheels]

Originally Posted by DoubleWasp
Seen it many times. Might be worth reviewing your impeller and the suction tract for your raw water. When water flow begins to go down, water can take the path of least resistance.

Also remove the caps off of the bottom of the manifolds. Even in fresh water, manifolds take on a black silt that clog them. Genuine Mercruiser/Quicksilver manifolds have screw-in plugs at the bottom of the manifolds. Take them out and you might be surprised. I've seen the black silt get so bad that they busted the manifolds apart like ice when they dried.

Manifold resistance many times is the cause of hot risers. I've seen too many engines get new risers on top of new manifolds just to have the same hot running issues.


Thanks DoubleWasp.

I replaced the cooling water intake hose and the path is clear from the scupper to the pump. The engine runs cool, too cool maybe, so I guess that the engine is getting sufficient water flow, but there is a restriction downstream of the feed to the port manifold and riser. I will check the whole cooling system, starting with the impeller, this Winter.