mrs peel wrote in
:

Ahoy, the mighty Yanmar YSB12 sputtered into life this evening for the
first time in many, many years. This is my first diesel and I have a
few questions. Quite a few, actually. It's kind of a long read now
that I look at it, I hope you're not too busy.
But First,..
I discovered it was seized about a year ago and added the miracle
product, Marvel Mystery Oil, to it's air inlet, pumped out the black
sludge from the crankcase and filled it with Marvel too. After rocking
the engine with the hand crank periodically over a few days it came
free.

That's why they call it "Marvel"...congrats!

I used automotive Chevron
10-30 for the rinses, using a 12v electric pump with a hose attached
to a pipe at the back of the crankcase, port side to suck out the oil.

Be informed car oil has been quietly derated for the last few years and
the detergent that gave the car oil the necessary C rating (like SF/CD)
has been removed by API in response. NEVER NEVER use car oil in even a
light duty diesel engine anymore. My personal feeling is they are trying
to wear out the gas engines quicker, right there at the end of the
warranty period, if possible.

I find out the Yanmar has no oil filter, but uses an oil screen.
Q: Is this behind the triangular plate with a T-handle to the left of
the crankshaft pulley as you are facing the forward end of the engine?
This is the only thing to filter the oil? I removed and cleaned it
with diesel fuel and drooled engine oil through it to wash out the
diesel, made sure the port was lined up to the strainer inlet and
reassembled it. Is there another strainer somewhere? I can't see how
this would do much.

Can't help on that model...sorry.

Q: Is Delo400 oil alright for a simple old one cylinder engine or
should I be using a C rated oil or a specific designer Yanmar oil? I
ask because I worked for someone who used Delo400 in an entire fleet
of diesel trucks and equipment and can't remember an oil related
failure. (they were mostly alcohol related).

Delo 400 or Rotella T are the finest engine oils available in the USA.
The new diesel ratings are different than CD. There is a number now in
the C rating...2 for 2-stroke diesels....4 for 4-stroke diesels. CH-4 is
the current 4-stroke diesel oil. Look on the Delo400 jug at the API
circle and you'll see it. Look at the car oil and it only has an S
rating for gas engines like the real cheap oil at the grocery store used
to.

Q: Are there engine Zincs to replace? Can someone describe where they
are on a YSB12?

Again, never worked on a YSB12 so can't help.

The Seawater Cooling Pump:
I found the water pump was a giant clod of green goo so I cleaned it
up and replaced the impeller and washers from an overpriced kit. As
this boat is on the hard I ran a garden hose to the pump inlet and
turned it on to a slow stream. There were no leaks before the engine
started but when it was cranking it showed a small, steady leak from
the lower slot where the slinger gets popped in. While running, water
was running freely out the slinger hole.
Q: Is this typical of a garden hose fed arrangement or does it sound
more like a bad rebuild? It doesn't look like much water was coming
out of the exhaust but was kind of hard to tell. I remember it took a
bit of violence to disassemble the pump and the reassembly did not go
smoothly either.

The pump shouldn't leak. Something is wrong.

The Prop:
After it was running I tried the throttle and the engine revs up and
down and goes into neutral, forward and reverse. Before I ran it the
prop would rotate very stiffly by hand. Now it turns easily. I noticed
a ring of moisture on the outboard side of the prop where the nut
holds it on.
Q: This means there's a leak from the bilge, right? I ran the hose in
there and filled it over the box where it goes through the keel before
I started the engine. Is this the way it's supposed to work? Passing
water? (only from the outside in).

Oh, oh....not good! You should NEVER run the prop out of water! Water
lubricates the stuffing box and the cutlass bearing just forward of the
prop. You probably tore it loose, tore into the stuffing that was dry
and may have ruined the rubber insert in the cutlass bearing. Don't put
it in the water without having the mechanic take a serious look at both.
If you tore the stuffing loose, it may sink the boat.

The Actual Running:
After opening the tank gate it took ages for fuel to fill the CAV
strainer and the electric fuel pump and the secondary filter. I bled
air at each union. Shouldn't this just rush through? I checked my new
gate, vent and clear line gauge at the tank and everything looks
alright.
I hooked up a battery charger and one 12v battery and cranked in 25
sec intervals for about 5 minutes. I got one pop and then sprayed 1/2
second of WD40 into the air intake, which seems to be just a naked
horn with no filter. After about 5 more minutes of shuddering and
gasping it ran raggedly with just a tiny squirt to keep it going and
finally ran on it's own. The was some blue/white smoke from the back
of the boat but not as much as I thought there would be. Also, there
was some smoke from the air intake which hung about in the cabin.
(engine cover off) Is this normal?

You're lucky it didn't explode, break the piston or the connecting rod.
NEVER spray starting fluid into these little diesels! What happens is
the engine is coming up on the compression stroke after you've loaded it
with flammables (WD-40 or starting fluid). Before it goes over TDC the
21:1 compression ratio makes the air charge loaded with starting fluid so
hot the starting fluid explodes, pushing the piston down, which turns the
crank the WRONG WAY! If the starter is engaged, it isn't going to be a
happy camper being turned against its will backwards. Imagine what that
might do to ring gears and starter pinions, not to mention starter
CURRENT trying to pull the guts out of the starter. Not good....

If that engine doesn't have a preheater, either in the intake or glow
plugs directly in the cylinders, a cheap hair dryer is your friend, but a
heat gun used to shrink shrink tubing is even hotter. HOT AIR is your
starting friend, not freezing-evaporating ether or WD-40. The hotter the
better. Fire hot air into its gullet as it cranks, giving the heat of
compression a boost to start off with. When injection happens, she'll
pop right off...after TDC, thank you!

Q: How do you shut it off? Turning the key doesn't do it. I finally
had to turn of the fuel tank and it still ran on and on. I was
concerned it wasn't getting enough cooling water so I put a rag up to
the air intake. This seemed a rough expedient but it did strangle it
finally.

Whoa! You certainly lead a charmed life! The diesel intake is wide open
to the air, there's no need of a throttle plate. It runs as fast as the
load and the injection will let it. What do you think would have
happened if it had sucked that rag into the intake?! A metal plate
larger than the intake is the only thing I'd ever put up to a runaway
diesel to choke it, strong enough NOT to be sucked in by 14 psi of
atmospheric pressure. Man, you are a lucky cuss....

The Alternator:
While running I have battery voltage at the alternator output but then
I noticed the panel light had been disconnected. It needs this to
excite the charger, right?

The alternator output terminal is directly connected to the battery. It
has battery voltage on it when the engine is off. The VOLTAGE at the
alternator output is what you need to measure. Off...about 12.2
Idle...about 13.5 Running faster....with a charged battery...about
14.2VDC.

The Fuel Pump:
When I turn the key on it ticks like a high powered English sports car
would but unlike a Lucas pump it doesn't pressurize and then turn off
and on as needed, it seems to just keep ticking. Is this normal?
That's it, that's all. I'd appreciate any advice anyone can offer the
DIYer. Thanks and smooth sailing.


I'd guess this model has a bypass pressure valve. Cars all have this
kind of arrangement, their pumps run continuously, now. The pump pumps
against the pressure loading spring of the valve, that opens at some
pressure relieving the pressure back to the tank. This creates a
constant pressure at the injection pump inlet, a good thing...(c;

I'd say it's normal.....unless fuel is pouring out somewhere...

On 21 Mar 2006 16:15:02 -0600, Dave wrote:

On Tue, 21 Mar 2006 21:14:33 GMT, mrs peel said:

Dave, can you try and describe how the main cockpit lever operates?
Maybe after it's loosened up I'll able to tell where "back past the
idle position is". Mine has just one lever which I'm guessing is 3
position but I don't know how the lever position is related to the
engine speed.


If you look at the back/bottom/inside of the "cockpit lever" you will
see a bracket that supports two cables. If you move the lever you will
note that one of the cables moves an inch or so very quickly and then
further movement of the lever has no more effect on that cable. Moving
the lever forward will extent or retract the cable and moving the
lever to the rear will move the cable in the opposite direction.
This is the shift cable and logically the initial movement of the
control lever puts the transmission in gear -- forward = go ahead and
back = go backward.

There is a second cable that moves in the same direction when the
lever is moved either forward or rearward, and moves for the whole
movement of the lever. This is the throttle cable.

There should be a third control. By pressing a button or pulling the
control lever outward, you should be able to operate only the throttle
without engaging the transmission. For warm up, etc.

Cheers



Anon
)
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