Forums > Sailing General

Exhaust hose path fail or something else

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Created by crewloose A week ago, 12 May 2019
crewloose
NSW, 15 posts
12 May 2019 10:10AM
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Is this avoided by lifting the height of the hose as it enters from the hull? Is it fair to say that a regularly used engine will keep enough pumped out, but an unused engine without any height in the hose allows this?

P.S. I didn't allow this to happen, but I made it my problem now.

Donk107
TAS, 2098 posts
12 May 2019 10:24AM
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crewloose said..

Is this avoided by lifting the height of the hose as it enters from the hull? Is it fair to say that a regularly used engine will keep enough pumped out, but an unused engine without any height in the hose allows this?

P.S. I didn't allow this to happen, but I made it my problem now.




Hi Crewloose

Is this water coming up the exhaust past the water trap or a leaking mixer elbow letting water back into the cylinder head

From what I read on the net it appear to be fairly common on GM series Yanmars

Regards Don

oldboyracer
NSW, 217 posts
12 May 2019 10:26AM
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Mine rises to deck Hight from the exhaust at waterline , I did have a similar issue when the anti syphon valve packed it in . Filled the entire engine with water ,that's how I found out the stop cock didn't close properly . Just a thought .

crewloose
NSW, 15 posts
12 May 2019 12:19PM
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Donk107 said..

crewloose said..

Is this avoided by lifting the height of the hose as it enters from the hull? Is it fair to say that a regularly used engine will keep enough pumped out, but an unused engine without any height in the hose allows this?

P.S. I didn't allow this to happen, but I made it my problem now.





Hi Crewloose

Is this water coming up the exhaust past the water trap or a leaking mixer elbow letting water back into the cylinder head

From what I read on the net it appear to be fairly common on GM series Yanmars

Regards Don


Hi Don,

Boat appears to only have a basic wet muffler, no riser/trap as such. It seems as if there is nothing in the exhaust elbow, the water exiting the heat exchanger is fed into the elbow and I assume that exhaust pressure does the rest? Engine is a VP 2K3.

Regards,

2bish
TAS, 306 posts
Tuesday , 14 May 2019 9:56AM
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Hi crewloose, do a google search "correct design for sea water cooled marine engine exhaust" and you'll pull up lots of diagrams that should help.

Here's one:
st2.ning.com/topology/rest/1.0/file/get/104608881?profile=original

crewloose
NSW, 15 posts
Thursday , 16 May 2019 11:42AM
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2bish said..
Hi crewloose, do a google search "correct design for sea water cooled marine engine exhaust" and you'll pull up lots of diagrams that should help.

Here's one:
st2.ning.com/topology/rest/1.0/file/get/104608881?profile=original


Very nice...

Ramona
NSW, 4886 posts
Thursday , 16 May 2019 6:02PM
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It all depends on whether the cylinder head is above or below the waterline of the vessel. If it is below the waterline you will need the gooseneck exhaust section. Otherwise the air vent will do the job. On my boat I have a water flow indicator that comes off the vent and runs a trickle of water under the teak slats in the cockpit and drains into the cockpit drain. When I shut down, the water stops and it becomes the anti siphon valve. If you have no problem starting your diesel and it starts with minimal cranking you should not have a problem with salt water entering the exhaust valves. If the engine takes a lot of cranking to start, leave the salt water intake closed until the engine fires.

crewloose
NSW, 15 posts
Saturday , 18 May 2019 8:43AM
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Ramona said..
It all depends on whether the cylinder head is above or below the waterline of the vessel....


All good info. The problem I'm assuming is mostly due to lack of use and the coupling of that with the absence of any kind of gooseneck to prevent the inevitable filling of the exhaust.

After I am up and running I'll look to lift the existing hose as it can be and go from there.

Cheers all



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"Exhaust hose path fail or something else" started by crewloose