Regarding automatic bilge siphon break Mercury 240 M2 EFI 1st gen

[rsatina2002]

Does anybody knows regarding the siphon hose with strainer outside starboard side of engine what's the use of it? I can find anything about this in the manual? I only read the past post here in the forum regarding the siphon break works when water goes inside your hull/transom and triggers automatic bilge pump to pump water out from your boat? Anybody knows what's the used about this? Thanks you Dr. Honda, I know you'll have an answer about this....

 

[Dr Honda]

The syphon uses the natural vacuum that is created in the jet nozzle. Hi velocity water going past the opening of a tube creates that vacuum. SO... there is a hose connected to that, and then comes into the boat via a passage internal of the pump unit. In the engine compartment, there is a fitting that the syphon hose hooks to. (It is gray from the factory) Since there's no valve in that system... yes, the water can flow back into the boat when the engine isn't running. The easy fix for that is... the hose should be looped up higher than the water level. From the factory, it was zip-tied up to where the water outlet hoses come out of the top of the heads. From there... the hose just drops back down into the bilge next to the engine. To help keep it from plugging up... the strainer is put in the end of the hose. (your picture)


And that's it. It's a simple system that draws water out of the bilge any time the engine is running.

 

[rsatina2002]

Thank you Dr Honda appreciate it... I cant find anything in the manual about this syphon hose.... because i left the drain plug open one time we launch the boat and the water level in the bilge didnt even go higher towards the engine... so automatic bilge pump and syphon break is activated. We manage to close it after an hour if launching...

 

[Lumps]

When we got our boat the screen on the end of the tube was soooo caked with crud it wasn't doing much. I was surprised to see it was silver in colour when I finally got it all cleaned out. seems to work properly now.

 

[seaningt]

Our boat almost sunk due to a clogged breather hole on the syphon break. The bulge pump ran until the battery died and the boat was full of water at the dock when we got to it in the morning.

It is a terrible design. We replaced the syphon break with a $10 check valve from amazon.