The large diameter hole you are looking at, is indeed the air intake. There
should be a semi-circular air induction tube casting attached there. Boats
don't normally have an air filter.
I know of no substitute for the fuel filter, although you could
substitute a completely different assembly I suppose. The filter elements
are still readily availabe.
Your engine was manufactured in 1976 or 1977, but the YSE and YSM
versions, which were manufactured two years previous to, and after the YSB
respectively, are the same engine in most respects.

--
Steve Thomas


"lupi" wrote in message
...
Ahoy, I just bought a small boat with a Yanmar YSB12 diesel in it. It
was owned by hooligans and it seems part of the motor is missing.
There is maybe some kind of hose missing in the front of the engine.
It's directly above the water pump and is an inlet about 2 inches
around. I can see some type of valve inside. This is the air intake?
Is there a picture on line somewhere so I can see what's missing?
Would a generic air filter and housing coupled to a tube work well
enough? Also, is there an inexpensive auto store filter that replaces
CAV 296, a paper filter that goes in the water trap? Also, what kind
of off-the-shelf oil can I use? There doesn't seem to be a lot of info
out there concerning these engines other than that they vibrate
violently at low rpm. I am in the usa. Thanks for your time.

Check out these sites for Yanmar related questions- they have message
boards specific for Yanmar engines and you can even order parts:

http://www.yanmarhelp.com/msgboard.mv

http://www.torresen.com/

Yes- that is the air-intake- do not use any paper-type filter or auto
filter. Get the manual for your engine and it explains everything you
need to know. I have a YSM12- the manual really helps.

Good luck!

"Steve" wrote in message ...
The large diameter hole you are looking at, is indeed the air intake. There
should be a semi-circular air induction tube casting attached there. Boats
don't normally have an air filter.
I know of no substitute for the fuel filter, although you could
substitute a completely different assembly I suppose. The filter elements
are still readily availabe.
Your engine was manufactured in 1976 or 1977, but the YSE and YSM
versions, which were manufactured two years previous to, and after the YSB
respectively, are the same engine in most respects.

--
Steve Thomas


"lupi" wrote in message
...
Ahoy, I just bought a small boat with a Yanmar YSB12 diesel in it. It
was owned by hooligans and it seems part of the motor is missing.
There is maybe some kind of hose missing in the front of the engine.
It's directly above the water pump and is an inlet about 2 inches
around. I can see some type of valve inside. This is the air intake?
Is there a picture on line somewhere so I can see what's missing?
Would a generic air filter and housing coupled to a tube work well
enough? Also, is there an inexpensive auto store filter that replaces
CAV 296, a paper filter that goes in the water trap? Also, what kind
of off-the-shelf oil can I use? There doesn't seem to be a lot of info
out there concerning these engines other than that they vibrate
violently at low rpm. I am in the usa. Thanks for your time.

I wouldn't put anything on the intake. It could interfere with the tuning.

Boats don't have air cleaners because there's not as much dust flying around
as on a road.


"lupi" wrote in message
...
On Tue, 14 Sep 2004 06:10:16 -0400, "Steve"
wrote:

The large diameter hole you are looking at, is indeed the air intake.
There
should be a semi-circular air induction tube casting attached there.
Boats
don't normally have an air filter.

Can you tell me what the air induction tube casting does? It's kind of
a horn? How long is it? If it's not intended to draw hot air off the
exhaust somewhere like a heat riser in a car intake or direct
turbulent air in some complicated manner, can I just hose clamp a flex
tube a few feet long on it? Why don't boats have air cleaners? Thanks
for your help.

I know of no substitute for the fuel filter, although you could
substitute a completely different assembly I suppose. The filter elements
are still readily availabe.

This part is the first thing fuel sees after 8 feet of hose from the
rusty tank. The CAV 296 labeled part is just a replacable cartridge
which sits inside the assembly. Inlet from tank- 296 cartridge nests
inside the assembly, above a glass bowl, just so you can see how much
water is present, I guess- and an outlet. The line continues to a
smaller widget on the engine which is another inline filter or a shut
off valve, I'm not sure yet.
Also, the fuel line leaves the tank (mounted just below the deck- it's
up as high as it can practically be) and then goes all the way to the
bilge and then goes back up to the filter in question, which I think
is a water trap, as it has a tap at the bottow of the glass bowl. The
dip in the line is for siphoning or antisiphoning of some type or is
it just a sloppy installation? Should the fuel delivery be downhill
all the way? It looks like the total drop, from the bottom of the tank
to the engine is only about 36 inches. Won't this be a problem in a
pitching sea?

Your engine was manufactured in 1976 or 1977, but the YSE and YSM
versions, which were manufactured two years previous to, and after the
YSB
respectively, are the same engine in most respects.



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