I think the whole point is that without a siphon break, it is "improperly
installed." If the original poster (with a Pearson 30) does not have siphon
break he is at risk. Since he stated quite explicitly that he was powering with
a following sea, turned the engine off, and then found water in the cylinder,
and we know that his engine is below the waterline, the lack of a siphon break
is a reasonable suspicion.

Jaxie, you're totally busted here - you clearly have no idea what you're
babbling about.



"JAXAshby" wrote in message
...
naive, the only time the "last two words" have any import is when you
(hereafter referred to as yo-yo) crank a non-starting engine over for an
extended period of time (during which yo-yo has left the cooling water intake
open) until the entire exhaust system downstream of the waterlift muffler has
been filled with water and yo-yo has loaded the back of yo-yo's boat down to
the point the exhaust outlet is under water and the exhaust outlet from the
muffler did raise sufficiently (yo-yo installed the outlet hose wrong) so that
the muffler inlet hose also fills with water yet the engine manifold outlet is
high enough yet still below the waterline that the *entire* downstream exhaust
system has been filled with water ...

... and then at that point yo-yo stops cranking the engine and settles back to
letter the water flow.

far more likely in the above situation (in which yo-yo has improperly
installed
the exhaust system) is that the water lift mufler fills up first and water
drains back into an open exhaust valve.

which, of course, would not have been prevented by any anti-siphon valve
because no siphoning occured.

you see, a yo-yo is a yo-yo.

Ok here's a direct quite. Read it slowly. Take your time.

"Problems occur because on almost all sailboats, and on many powerboats,
the engine is installed below the waterline. Even if it's not below the
waterline when the boat is at rest, the engine may well end up there
when the boat heels, or when it is heavily loaded. This latter case can
be particularly dangerous: because the boat's designer or engine
installer may not have adequately planned for it. If the engine is or
any time below the waterline, any cooling circuit that allows raw water
into the exhaust has the potential to set up a siphon action. Water may
siphon in from the water injection side; or, if the exhaust outlet is
below the waterline, from the exhaust outlet side."

See the last two words???

Cheers

JAXAshby wrote:

nave, go look at a wet exhaust, any wet exhaust. you simply don't
understand
what such is.


Dud? Let me explain at a level a child should understand. You run the
engine -it gets hot. You turn it off. You raise the sails so the boat
heels and puts the exhaust under water. The engine cools and water gets
sucked in 'cos the siphon break valve no longer works...

get it?

Cheers

JAXAshby wrote:

Now tell us why you think you don't need an antisiphon valve. Vague
references to gas laws are required.


you can't siphon water uphill using the weight of exhaust gas going

downhill.

dud!