Is it necessary to have a siphon fitting in the salt water line to the mixing elbow? I have one now that is corroded and leaking into the bilge when the engine is running. I'm thinking of leaving it out as in the YANMAR diagrams there does not seem to be a siphon shown. Any ideas?
1990 Hunter 30 2gm20f mixing elbow
- Thread starter Ray1156
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Depends who you ask
I posted this exact question about 2 years ago and got answers from you don't need it because you are above the water line to you should absolutely have it because you can flood the mixing elbow and fill your engine with water.
I can tell you that I took mine out and have not had an issue. Good ridance to that leaking siphon valve.
I cannot see how a siphon can be drawn from the mixing elbow if it is above the water line and unless someone can come up with a really good scenario, mine will continue to be off and leak free!
I posted this exact question about 2 years ago and got answers from you don't need it because you are above the water line to you should absolutely have it because you can flood the mixing elbow and fill your engine with water.
I can tell you that I took mine out and have not had an issue. Good ridance to that leaking siphon valve.
I cannot see how a siphon can be drawn from the mixing elbow if it is above the water line and unless someone can come up with a really good scenario, mine will continue to be off and leak free!
Siphon Needed
This very thing happened to my boat before I bought it. No siphon loop, sucked in water, etc. Result: A new engine. The dealer disclosed this is what had happened, and the surveyor independently came to the same conclusion. Twas good for me, though, because I got a used boat with 60 hours on a new engine.
This very thing happened to my boat before I bought it. No siphon loop, sucked in water, etc. Result: A new engine. The dealer disclosed this is what had happened, and the surveyor independently came to the same conclusion. Twas good for me, though, because I got a used boat with 60 hours on a new engine.
Well I've same engine and just replaced the mixing elbow. Both new and old doesn't have the siphon tube at apex of the mixing elbow. My mixing elbow outlet goes to a siliencer(?) (a large 6"diameter x 12" length cylinder before going to a loop above waterline then out just maybe 4" below waterline. I don't have water back flow problem.
Ken, Hunter 326
Ken, Hunter 326
mixing elbow
I just replaced the elbow on my 29.5 and got a totally different style than the original. It goes down at about a 45 degree angle instead of a U shape it is also steel lined with stainless.
It does not have a siphon valve, but does have a raw water injector. The siphon is connectd to the raw water intake hose, and was also corroded, it was stainless steel with a plastic vent connected with a steel coupler.The corosion enlarged it and cracked the plastic. In my search for a new one.you had to buy a whole new assemble ( a different size of course) and work out how to adapt it.
Bottom line. It was there, so I put it back.
I just replaced the elbow on my 29.5 and got a totally different style than the original. It goes down at about a 45 degree angle instead of a U shape it is also steel lined with stainless.
It does not have a siphon valve, but does have a raw water injector. The siphon is connectd to the raw water intake hose, and was also corroded, it was stainless steel with a plastic vent connected with a steel coupler.The corosion enlarged it and cracked the plastic. In my search for a new one.you had to buy a whole new assemble ( a different size of course) and work out how to adapt it.
Bottom line. It was there, so I put it back.
45deg mixing elbow
Pretty messed up with rust/corrosions and restriction?
John, when you removed the old mixing elbow, how does it look inside?
Pretty messed up with rust/corrosions and restriction?
To Siphon or Not
While your engine is running the raw water is flowing towards the elbow and the low point, your muffler/silencer. The vaccum created by the water running down towards the muffler has the potential to continue after you stop the engine. With no exhaust pressure the potential to fill the exhaust line at least to the the top of your exhast loop exists. There are two ways to positively prevent this. 1. Shut your raw water through hull every time you stop the engine. 2. Install an anti-siphon/vaccum break in the raw water line after the raw water pump and above the waterline. Anything less than one of the above is a gamble.
While your engine is running the raw water is flowing towards the elbow and the low point, your muffler/silencer. The vaccum created by the water running down towards the muffler has the potential to continue after you stop the engine. With no exhaust pressure the potential to fill the exhaust line at least to the the top of your exhast loop exists. There are two ways to positively prevent this. 1. Shut your raw water through hull every time you stop the engine. 2. Install an anti-siphon/vaccum break in the raw water line after the raw water pump and above the waterline. Anything less than one of the above is a gamble.
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