Westerbeke need a siphon break??

Jimmy Buoy

Well-Known Member
Dec 3, 2008
2,454
Sarnia, Ontario, Canada
Boat Info
2003 Cobalt 293
Engines
Twin Volvo-Penta 5.0 270hp & DuoProps
Hi all!

I've been reading one too many stories of gennys dying from water injestion as a result of not having a siphon break. So I've taken a look at my Westerbeke 4.5 BCGB - no siphon break at the top of the cooling hose loop.:huh:

I've haven't had a problem and the unit appears to be original, but every time I go to fire it up I'm concerned.:smt009

Will it crank one time too many and gulp water like others??:wow:

Is it safe/accurate to say "if it needed a siphon break, Sea Ray would've installed one"?:huh:

It seems like a cheap and easy part to install. What do you think gang?:grin:
 
Can someone please comment as to if they have one of these siphon breaks on their generator? I don't and am getting water in my oil. Local Sea Ray dealer says every boat he's look at has one, but I know of 2 41 dancers that do not have one. Curious as to what others have.
Thanks
 
My 88 and my neighbors 87 does not
 
A siphon break will not fix over-cranking and filling the exhaust system and consequently the engine with water. The siphon break will, however, prevent water from siphoning into the exhaust system when the generator's exhaust raw water inlet is near or below the water level.
 
We have one and it leaks a little water into the bilge. Generator is 8KW Quicksilver.
Can someone explain how over cranking can get water into the engine. That is how I put propylene glycol (Pink) into my main engines in the fall. I put in 4 gallons. I pour it into the strainer and crank the engine with the wire off between the coil and the distributor.
 
We have one and it leaks a little water into the bilge. Generator is 8KW Quicksilver.
Can someone explain how over cranking can get water into the engine. That is how I put propylene glycol (Pink) into my main engines in the fall. I put in 4 gallons. I pour it into the strainer and crank the engine with the wire off between the coil and the distributor.
The raw water pump turns during cranking and delivers water to the exhaust riser; the water flows to the lift muffler and eventually backs up and fills the exhaust riser and then flows into the engine's exhaust ports. As the engine is not running there is no exhaust flow and pressure to drive the water from the lift muffler.
 
If memory serves me correctly I believe Sea Ray installed siphon breaks beginning in 1995 or 1996 on all boats with generators. The generator manufacturer's required them.
 
My 1986 390EC has one for the Westerbeke 8kw. It was on the boat 8 years ago when I bought it. Strongly recommended
 
Hey guys, this post was started over 9yrs ago. Maybe time for an update??

I never did add a siphon break to the system and have used the generator each season without any issues.
 
I was not the one who originally started this thread a while back, but I resurrected it. I was Googling to help find a reason for water in my oil on my Westerbeke generator and ran across the topic on CSR. And like many threads, the final fix was not mentioned. But it sounds like the water in my genny is getting there because I don’t have one of these “siphon breaks”. Basically, it’s a loop in the raw water hose that runs from the heat exchanger to the exhaust elbow. On my genny, this hose enters the exhaust elbow with the fitting in the elbow facing straight down. So there’s no loop.
In my owner’s manual, Westerbeke shows the hose running just as mine is. But the following year, their owner’s manual shows the hose entering from the top following a loop in the hose with the fitting in the elbow pointing straight up. And they make a point that this loop is recommended. Pretty piss poor communication.
So from the responses on this site, most if not all have the hose loop in that creates this siphon break. Now what I don’t understand is what type of siphon break. There’s three I found. One is simply looping the hose upwards into the elbow fitting pointing straight up. Then there’s a separate 180° loop that connects the water hose to the elbow (attached in pic). Then there’s a siphon valve that somehow fits into the water hose. Not sure what everyone else has? The Westerbeke part numbers are 049954 and 33327, so Google and see.
Not sure what kind of damage I’ve done to my genny? I just got the boat and the genny’s got 277 hours. Starts fine and runs fine. Not sure when this problem started. Do I need to just make the water hose a loop, or make the loop and buy a valve?
 

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Maybe, maybe not - if your generators exhaust water inlet is below 12 inches above the water line you need a loop at least 12 inches above the water line and siphon (vacuum) break valve at the loop high point. Regardless, It's good practice to have a loop and vacuum breaker well up into the boat's gunnel.
 
Maybe, maybe not - if your generators exhaust water inlet is below 12 inches above the water line you need a loop at least 12 inches above the water line and siphon (vacuum) break valve at the loop high point. Regardless, It's good practice to have a loop and vacuum breaker well up into the boat's gunnel.

Tom, always appreciate your very informative post, especially the electrical/electronics stuff. But this one I'm having a hard time wrapping my head around. Thanks, Mitch
 
A siphon break will not fix over-cranking and filling the exhaust system and consequently the engine with water. The siphon break will, however, prevent water from siphoning into the exhaust system when the generator's exhaust raw water inlet is near or below the water level.

I guess it's "raw water inlet near or below the water level/line" that is throwing me a curve as I would think it should always be below?
 
Tom, always appreciate your very informative post, especially the electrical/electronics stuff. But this one I'm having a hard time wrapping my head around. Thanks, Mitch
Understand, probably needed to be a bit more descriptive - It's important to understand where the raw water inlet for the generator's exhaust is relative to the water level on the boat. If that water connection on the generator's exhaust is below the water line then a loop and anti-siphon valve is required. However, the loop and valve are good practice for all installations. There appear to be some examples of factory installations that are marginal (SR did do several bulletins over the years). Most water intrusion cases are simply from over cranking the engine. Maybe this pic better explains -
siphon.jpg
 
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if it helps you can sort of see the siphon break in this pic of my genny and starboard engine.....I have not really studied how it works so really can't answer questions about it....

cliff

starboard engine and generator.jpg
 

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