Dennis, Your picture shows two vented loops, vented into each other. Possibly an engine cooling line and a bilge pump. I'm no expert but I'm not sure if that is proper. It could cause a problem if a vent valve fails open.
This Forespar video explains how they work. https://www.youtube.com/watch?v=llT3VAAMsDE Chuck S > On 06/30/2022 11:15 AM Dennis C. via CnC-List <cnc-list@cnc-list.com> > wrote: > > > John, > > Here's a pic of the vented wet exhaust riser on Touche'. At least I > think that's what it is. > > > https://drive.google.com/file/d/1r-3xSbChZeio35MrFSmtN03y6VW6ugKz/view?usp=sharing > > It's the fiberglass loop at the top. Don't ask me how it works. Don't > ask me about the loop at the other end of the little gray hose, either. I'm > completely ignorant of this configuration. > -- > Dennis C. > Touche' 35-1 #83 > Mandeville, LA > > On Thu, Jun 30, 2022 at 9:46 AM John Read via CnC-List > <cnc-list@cnc-list.com mailto:cnc-list@cnc-list.com > wrote: > > > > > > Interesting – have not heard or seen vented loops used this way. > > My 34 does not have them and no problems in 40 years > > > > > > > > John Read > > > > Legacy III > > > > 1982 C&C 34 > > > > Noank, CT > > > > > > > > From: CHARLES SCHEAFFER via CnC-List [mailto:cnc-list@cnc-list.com > > mailto:cnc-list@cnc-list.com ] > > Sent: Wednesday, June 29, 2022 5:20 PM > > To: CNC boat owners, cnc-list > > Cc: CHARLES SCHEAFFER > > Subject: Stus-List vented loops > > > > > > > > Learned the hard way how to test vented loops. > > > > > > > > I was changing engine hoses and came upon an original, 33 year old, > > bronze, vented loop for the engine cooling water. It's located between the > > heat exchanger and the injection elbow of the exhaust riser. It's purpose > > is to break a siphon and prevent water flooding the engine and the boat > > when the engine is off. Mine was filled with scale and no longer > > operational. > > > > > > > > The following comes from info included with a new Forespar vented > > loop. To test a vented loop, you blow air through the vent from outside > > into the tubing, through the "duck bill" rubber thing, and that's it. If > > air won't penetrate, it's clogged and should be cleaned. If the thing > > leaks, it probably needs cleaning or a new rubber duck bill. > > > > > > > > I replaced the Forespar rubber duckbill, $15, on my bilge pump hose > > and I replaced the entire loop fitting $44 on the engine hose using a > > Forespar 5/8" vented loop. Now both of my vented loops use the same > > duckbill vent and have the same size retaining nut so a simple clear two > > foot length of 3/4" hose can be pushed over the fitting to facilitate > > testing either vented loop. > > > > > > > > I have to add that I never had a problem in twenty years of > > ownership and ingnored these items until I started replacing hoses. I'd be > > glad to hear anyone else's ideas on this. > > > > > > > > Chuck S > > > > > > > > > > > > > > > > > > > >
