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Old 11-09-2019, 16:27   #1
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Methods to reduce water sitting in exhaust and preventing hydrolocking

So as I am awaiting my turbo rebuild, I am trying to think through on what caused the problems, what problems are down stream of the engine and ways I can prevent future issues from occurring.

I recieved a new mixing elbow and as such wanted to compare the old to the new. When I pulled the elbow out of the exhaust hose, I realized the hose running from the elbow to the lift riser(?) has standing water. First, I believe this may be due to the angle that the hose runs from the elbow to the riser, but I believe this also is due to possibly the riser not being large enough?

Does anyone have any recommendations on resources for how a proper exhaust system be installed?
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Old 11-09-2019, 16:55   #2
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Re: Methods to reduce water sitting in exhaust and preventing hydrolocking

Picture........ more the better
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Old 11-09-2019, 17:45   #3
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Re: Methods to reduce water sitting in exhaust and preventing hydrolocking

Lots of info out there on water lift mufflers.... Google "water lift muffler installation", or check out "Centek.com", etc..

For sure there should be no sagging hoses or standing water in the hose from the exhaust elbow to the water lift muffler, and generally no more than an inch or two standing water in the bottom of the muffler itself upon engine shutdown.

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Old 11-09-2019, 18:56   #4
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Re: Methods to reduce water sitting in exhaust and preventing hydrolocking

The riser diameter should be smaller in the rise, then larger downhill to the outlet. You need to accelerate the gasses in that run. All uphill small, all downhill big.

Sometimes wind and "breathing" happens and salty air can be blown through the engine. This will create rust. Best is to install an inline flapper valve, like a non-return valve.
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Old 12-09-2019, 05:27   #5
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Re: Methods to reduce water sitting in exhaust and preventing hydrolocking

Exhaust System Fundamentals ~ by Dave Gerr ➥ Exhaust System Fundamentals ~ by Dave Gerr - Part 1 = 10 pages Part 2 = 12 pages Dave Gerr is director of the Westlawn Institute of Marine Technology, a practicing Yacht Designer, and noted author of: "The... Cruisers & Sailing Photo Gallery




Yanmar Exhaust Diagram ➥ Yanmar Exhaust Diagram - Cruisers & Sailing Photo Gallery

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Old 12-09-2019, 05:53   #6
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Re: Methods to reduce water sitting in exhaust and preventing hydrolocking



The only problem Iíve got with those diagrams is theyíre not designed for a craft that heels. The waterlift should be centerline when the boat is able to heel without the engine running.
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Old 12-09-2019, 09:44   #7
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Re: Methods to reduce water sitting in exhaust and preventing hydrolocking

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The only problem Iíve got with those diagrams is theyíre not designed for a craft that heels. The waterlift should be centerline when the boat is able to heel without the engine running.
I believe that all of the systems illustrated are intended to be installed on the centerline of the vessel. The illustrations are a little misleading in that the transom thru which the exhaust exits looks a lot like the side of a boat rather than the stern.

The most important element of exhaust system design for a sailboat is that the outlet of a waterlift muffler must go straight up to a point above the water line before making a 180 turn and heading for the stern.

I just rebuilt a Ford Lehman 120 that was flooded due to a failure to route the exhaust straight up as I've described. Obviously, we're fixing that problem now.

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Old 12-09-2019, 11:32   #8
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Re: Methods to reduce water sitting in exhaust and preventing hydrolocking

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..........Sometimes wind and "breathing" happens and salty air can be blown through the engine. This will create rust. Best is to install an inline flapper valve, like a non-return valve.

Exhaust flapper valves need periodic inspection and rarely receive it! After several years they are known to become unhinged (literally), rendering them useless and sometimes causing partial obstruction. Better yet is to dispense with the flap valve and install a full-bore diameter ball valve at or near the exhaust exit.
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Old 12-09-2019, 17:03   #9
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Re: Methods to reduce water sitting in exhaust and preventing hydrolocking

my engine is low in the boat and there is no room for the minimum clearances on the usual diagrams. I just shut the seawater intake off two minutes before the engine shuts down. This clears the exhaust system of water, and I have a flapper valve on the stern
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Old 12-09-2019, 19:16   #10
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Re: Methods to reduce water sitting in exhaust and preventing hydrolocking

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Originally Posted by peter loveridge View Post
my engine is low in the boat and there is no room for the minimum clearances on the usual diagrams. I just shut the seawater intake off two minutes before the engine shuts down. This clears the exhaust system of water, and I have a flapper valve on the stern


Surprised you havenít had multiple Impeller failures.
I was going to suggest a ball valve after the pump, close it, rev the engine like Yanmar suggests anyway and shut it down.
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Old 12-09-2019, 20:02   #11
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Re: Methods to reduce water sitting in exhaust and preventing hydrolocking

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Originally Posted by peter loveridge View Post
my engine is low in the boat and there is no room for the minimum clearances on the usual diagrams. I just shut the seawater intake off two minutes before the engine shuts down. This clears the exhaust system of water, and I have a flapper valve on the stern

How many times would I have sunk our boat if it had that set -up? Good for you sir
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Old 13-09-2019, 08:32   #12
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Re: Methods to reduce water sitting in exhaust and preventing hydrolocking

If you'd like to contact me direct at jmardall@comcast.net, I'll send you the Vetus Academy training module on wet exhaust systems, which covers these issues extensively.
All the best
John Mardall
Vetus Maxwell Boat Equipment
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Old 13-09-2019, 09:26   #13
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Re: Methods to reduce water sitting in exhaust and preventing hydrolocking

A lot of good info in the above replys.

Take a look on the Seaboard Marine website ( sbmar.com ) for ideas and pictures and videos about preventing turbo death. Whatever protects the turbo protects the Elbow at the same time.

Go to the tab marked under Tony's Tips.
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Old 13-09-2019, 16:33   #14
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Re: Methods to reduce water sitting in exhaust and preventing hydrolocking

Yup, that was what I was thinking, if I protect the elbow, the turbo inherently is protected( and viceversa).

Sbmar has some great info - just started looking at that.

Tine to start digging around, measuring and determining where water levels are figuring out how to make ours better as its obvious water is sitting in the exhaust and in turn causing the rot to occur.
Quote:
Originally Posted by Squanderbucks View Post
A lot of good info in the above replys.

Take a look on the Seaboard Marine website ( sbmar.com ) for ideas and pictures and videos about preventing turbo death. Whatever protects the turbo protects the Elbow at the same time.

Go to the tab marked under Tony's Tips.
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Old 13-09-2019, 21:34   #15
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Re: Methods to reduce water sitting in exhaust and preventing hydrolocking

I have valves on my water mufflers that open when the pressure of the exhaust is gone as the engine is shut down. That way the engine starts with low back pressure, handy with an older engine. Also you can crank for awhile without worrying about water building and flowing into the engine. Since the engine is stopped, the muffler drain is open.
I don't like turbo engines, and if I have the hp I need available in a natural, I go that way. But I've owned many turbos and ran many others. I solve the problem of early turbo failure by replacing the turbo bearings and seals at about half life. A lot cheaper than a new/rebuilt turbo and easy to do. Also clean oil. Turbo bearings either get their lube oil thru a small passage in the head or an outside tube. The oil cools the bearings. Dirty oil leaves deposits restricting the flow. If the flow is reduced too much the bearings get too hot, degrade over time and enough heat will ruin the seals.
I just rebuild my Ford PU turbo for about $100.



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