Exhaust Hose?

Dougal

Dougal

Well-Known Member
Joined
6 Dec 2006
Messages
895
Location
Wiltshire / Brittany (50/50)
Visit site
I have to replace the entire engine exhaust hose (ouch). There's about 4.5m of 51mm ID hose. Engine and Vetus water trap are below the water line. Am I correct in asumming that with this setup, I must also have a raised anti siphon loop in the hose?
 
May I suggest

You look at the Vetus catalogue, online is OK, they detail the various scenarios according to waterline.
 
The term "anti-syphon loop" in this context is perhaps a misnomer. What is necessary is for the exhaust hose to be routed so that it cannot back-fill from the hull outlet under all expected angles of boat heel etc. This may require an upward loop.
The water trap takes residual water in the hose after engine shut-down.
PS; An anti-syphon device in the cooling water line is a different issue and will probably be necessary from your description
 
It is often called a swan or goose neck which is a loop in the exhaust as far above the waterline as possible just before the outlet. It can be achieved with either a loop in the hose - the latest hose is better at this because it bends more easily - or a plastic goose neck which can be found in the Vetus catalogue.
 
If you cant make a gooseneck at the transom, can you make it right after the waterlock maybe? I have one after that and one at the transom. With gooseneck right after the waterlock there is less hose length ( 1 meter apprx.?) so much less water will return to waterlock when sutting down.
 
Dougal said:
The exhaust exit is in the transom. What about just fitting a flapped exit instead? I can JUST get a loop in end but it's bloody hard.
Click to expand...

If the "JUST" is due to the rigidity of the hose, you might find it easier to fit a moulded plastic swan-neck, which will also occupy less space. They're in the Vetus catalogue, with which you seem painfully familiar ;)
As said, the same catalogue should tell you all you need to know about exhaust installation. Sounds like you need both a swan-neck and a siphon break, as earlybird explains.
 
Alas, I am indeed getting FAR too familiar with all the damn catalogues:( And point well taken re the extra work. I also once had to rebuild a 4 cylinder petrol engine (Atomic 4) for the very same reason. Damn, that hose is expensive!
On a brighter note, for all those that helped with my engine rewire, I'm up & running. And very neat it is too;)
 
The Vetus website/catalogue has helpful diagrams and explanations of the need. So also does the Beta Marine Installation Guide. Here's a page from the latter....

42101606625_c29b33261f_b.jpg


I've gone for a waterlock, a gooseneck - AND an anti-siphon loop between the heat exchanger outlet and the mixer bend injection inlet, as shown but not expensive Vetus - simply a rugged corrugated rubber hose. This latter has a tiny air break tube inserted as high as possible, which provides a visible 'piddle' into the cockpit to prove that cooling water is flowing. The modest cost of putting this in is probably a couple of orders of magnitude less than the cost of repairing a hydraulic-locked engine. The CEO of Beta Marine, amused at my iggorance, politely insisted.....
 
one quick heads up.
If your hose is OE and you are replacing it with "something similar" ,possibly to save cash,be aware it is very likely to have much thinner wall, possibly due to better material being available ?
This means that your existing hose clamps (if you intend re using them) will not tighten up sufficiently and will leak,
You may well ask how I know.:)
 
Last edited:
oldgit said:
one quick heads up.
If your hose is OE and you are replacing it with "something similar" ,possibly to save cash,be aware it is very likely to have much thinner wall, possibly due to better material being available ?
This means that your existing hose clamps (if you intend re using them) will not tighten up sufficiently and will leak,
You may well ask how I know.:)
Click to expand...

Wow thanks! I wouldn't have thought of that either.
 
Can I ask, why you need to replace your exhaust hose?
(You may have seen a recent thread where I am wondering if mine needs replacing due to possible partial internal collapse, restricting exhaust flow and max revs. )
 
Dougal said:
Wow thanks! I wouldn't have thought of that either.
Click to expand...

......and neither did I, just replaced hose and tightened original stainless clamps (not jubilee type hose clips) to max.
Mysterious slow leak into bilge, examination produced a drip drip weep from clamp only when under way.
Bought small clamps and resealed with dab of CT1 for belt and braces.
 
You must log in or register to reply here.

Share this page

Top