Cooling water loop and Anti Siphon

[Bryan Janeway]

Good day all,

Just picked up a Northern 29 last fall and slowly taking off the old and putting on the new properly.

I see the anti siphon valve in the online catalog and was wondering if I should replace my existing config to include the anti siphon valve or is this also an acceptable method??? I am changing out the water lines and exhaust lines and the galvanized to include proper fittings.

As you can see from the picture a pipe is pulled off the top of the loop and connected to the exhaust after the exhaust loop.

The engine currently runs very well and water temperature appears to be in the 160 170 degree range. So no problems exist other than the old lines appear to be from a time before Noah's Ark.

If you need more info or a better pic I will try and come up with one.

Thanks

Bryan

[Dave Neptune]

Brian, first welcome to the MMI Afourian Forum.

Where does the rest of the water inject into the exhaust? It would work as long as it is above the water line on both tacs.

Dave Neptune

[Bryan Janeway]

That picture is well above water. The boat has a high freeboard so I'd have to be hiked over something fierce before that portion of the boat was below the waterline. The injection to the water lift is just above the water line. When hiked over it may be a touch below.

The water lift muffler is adjacent the engine. The exhaust exits the manifold and takes a turn to the left. The loop off the cooling water goes up into the cupboard pictured and is injected into the top of the exhaust. The remainder of the water comes back down the loop and goes into the water lift.

The reason I am concerned is as I was getting the engine started a few weeks ago I had forgot to connect that tube at the top. OOPS.... and a significant amount of water was ejected out the top. Shouldn't "all" of that water go in the water lift?? Obviously all of the cooling water goes into the exhaust just at two different points.

Thanks for helping me with my concerns.

Looking forward to advice

[ndutton]

Do I understand the assembly pictured is not the exhaust water injection? The description mentioned water injection "at the top" and this appears to be other than the top. If I'm reading correctly it appears you have a vented loop as an anti-siphon although it seems to be at an odd location.

Can you provide a drawing of the entire system?

[Dave Neptune]

Brian, all that is needed is enough opening at the "loop" to allow air back in when the engine is shut down. Yes indeed as much of the watter as possible should go to the water lift. an 1'8" tube fitting would be fine at the loop. I had a similar set up for a while but my "loop" "vented" to the cockpit drain not back into the exhaust.

Dave Neptune

[joe_db]

What am I looking at?

[BobMcD]

Hey Bryan,
I also have a Northern 29 !
My exhaust is very similar to yours.
I agree with Neil that the loop at the top is a vented loop to prevent water siphoning back into the engine.
It works well.

[ndutton]

We usually see anti-siphon protection as high in the water injection hose as possible. A valve or an open loop both work fine as long as the valve isn't clogged or stuck. I prefer the open loop by far. No moving parts to fail and no spitting.

[chapster5]

Bryan
I also have a Northern 29 and my set up looks much like yours.Hopefully that gives you piece of mind. Looks like their are at least 3 of us on here with the Northern29.

They are a great old boat , cockpit a little small but its is normally just the Admiral and myself.

Chapster5

[joe_db]

That looks like the hot section AND the wet section use rubber hose? Am I looking at a riser or ????