Anti syphon great idea

[Rick9619]

For those of you like me who have been frustrated with the location of your anti syphon, here is a pretty cool one. Made by Vetus. Got it at the local marine exchange. It hooks up just like the standard ones BUT it has a vent on top that you hook a hose up to, so when you momentarily forget to close the raw water and your rolling on the hook, dont despair. I routed the hose back down to the drain for the stuffing box. It was $65 but to save the top of my motor... Priceless!CheersRick

 

[Peggie Hall HeadMistress]

Downside to vent hose on vented loop...

Mineral and salt buildup can clog up the vent and hose in a relatively short time...turning it the loop into an UNvented loop. And because a loop with a hose on it is "out of sight, out of mind," people never check it to know it needs cleaning out.The best solution: put the loop high enough to make a hose unnecessary...and remember to clean the air valve in it once a month as preventive maintenance.

 

[Don12364]

Not Sure

Rick,The whole idea is to allow air into the top of the AS bend so that the system can drain when the engine is stopped. I may have misunderstood your description but will this be the case if the vent is connected to the stuffing box as you describe? Vetus state it should be to a skin fitting above WL.I thought of fitting one of these but feel that, unless the vent tube rises to a point considerably above the injection bend, the cooling water might flow from the vent rather than entering the exhaust system via the water injection bend.

 

[Rick9619]

Perhaps I was unclear

Thanks Peggy et al. I got the model V which is an anti syphon valve, not the other one which continually vents water. It works just like the standard one we have stock on the hunter. I put it exactly where the original one is located... near the top of the engine bay, and yes right above the header tank of my 3GM30F. If it backfills, it just spills the seawater out the top INTO a hose which I just routed down along the engine to my "alleyway" where the stuffing box is located.... not hooked up to the shaft log in any fashion. It goes through the drain there and into the bilge. And yes I will put it on my regular maintenance schedule. Seems like a good idea. I did however keep my original. I know guys like "Obi Fred" have other solutions like moving the darn thing, but this keeps the loop high and near the mixing elbow. Clear as mud?CheersRick

 

[abe]

Peggy, all new boats come with an anti syphon...

to prevent someone from cranking the engine too long an getting water from the tail pipe back into the engine. Raising a loop will not solve the problem...unless someone ones to climb the mast at the 32ft level. In addition, on Hunters these loops are right where you can see them when you check oil, belts, and so on.abe

 

[Moody Buccaneer]

Abe

Can you explain how an anti-siphon prevents someone from cranking the engine too long and getting water from the tail pipe back into the engine? I don't think that is how the valve works.

 

[NYSail]

Anti-syphon

I always thought the anti-syphone valve is there so when you turn the engine off, water does not syphone into the engine due to the back preasure created by the engine.Anti-syphones are different from vented loops....I always thoughtGreg

 

[Rick9619]

More efficient anti syphon

Thanks Seadaddler. Great expample and good to know they appear to be stock on the new Hunters (mine is a 95 336). I installed mine very similar and the clear drain hose as I said. It protects your engine, areas of importance. Abe, my exhaust outlet is starboard side just on the underside of the hull. I was told if my engine is not running, raw water seacock open, and that exhaust pipe is being "stuffed" in the water, then it can travel up the hose past the mixing elbow, and drain down into the exhaust manifold and move on from there. It has always been my understanding simply put, that the valve is there to allow air into or vent the system AND OR give an exit point for any seawater that might not travel its normal route. Bottom line... I just thought it was a great improvment over the original. Apparently Hunter agrees.CheersRick

 

[abe]

Your right, my mistake got my mouth from my a**..

confused. I just wanted to say that continous cranking can cause salt water into the engine and that the antisyphon vaulve helps avoid that.My boat is stern heavy and the exaust is just at the water line... potentially you can crank get water out the exaust but when you stop you can potentially get water coming back. You try to re crank and now you have water from both ends.