What is this part for on heat exchanger

[Michel C]

i have a Yanmar 4JH2E and would like to know what this part is (see picture), what is its function etc.
I've searched the manuals and parts catalogues but couldn't find it.
Also, i don't know if it's missing a cap or not.
Any help would be appreciated.
Thanks
Michel

 

[Calif. Ted]

It's a vented loop, an anti-siphon device, I can't tell from the picture if yours is all there.
http://shop.catalinaowners.com/prod.php?11907/Vented+Loops

 

[kloudie1]

Ted is correct.. there should be a one-way valve on that nipple at the top of the loop.. to let air into the top to break a possible syphon that would back fill the engine with sea water. It looks like the valve is missing. They come in different sizes, so you'll have to know the hose size. http://www.ebay.com/itm/SCOT-3-4-VE...ash=item35ebb6040e:g:-M4AAOSwmmxW2q-q&vxp=mtr
and for info:
http://www.betamarinenc.com/exhaust-design/
The connecting hoses look a bit too short to allow the engine to rock and bump on its soft mounts .. ya might want to check that out ..

 

[Michel C]

Thanks guys...

 

[JamesG161]

The top venting nipple has to be "plugged" or you would be spewing water from the top, when you engine runs. The panel shows no water damage.

This high point vent, on most sea water designs, only helps if your flex vain impeller is worn.
Jim...