Where do I connect this vacuum line? ( '89 Merc 150 V6 w/ Carbs)

I'm rebuilding an old merc, and I have one vacuum line hanging, and I can't figure out where it goes
(see red arrows in attached photo).

It's a 1989 V6 150 Merc with WH-40 Carbs (S/N 0B381657)

As the attached photo shows, the line connects to the block on the port side beneath the middle carb.
You can see that I capped the other end of the line with a screw, because I can't find anyplace to connect it.

I believe there are two lines that connect to the block in that area. One of them runs from the port side to the starboard side
and connects to a port on the block that is basically on the side of the one of the cylinders. That line is and was hooked up.

The mystery line is the other line that connects to the front of the block near the line that I just described.


-Phil

P.S. -- Bonus points for anyone who knows what these (and this) vacuum line does!!

Attachment 369697

Is the oil inj functioning?

goes to the bottom of air box, if your not running the air block just plug it

Attachment 369698

Hope this helps.

Quote:

---

Originally Posted by XstreamVking

Is the oil inj functioning?

---

It's hooked up, but I haven't fired the motor up yet, and the motor is new to me so I don't know...
but I *do* know how to check, and I realize that it's critical. I'll be running pre-mix for the first tank
anyway, because the motor sat unused for many years so I was told to treat it like a new break-in.

Quote:

---

Originally Posted by topgun marine

goes to the bottom of air box, if your not running the air block just plug it

---

Thank you. I will check the airbox and look for where it connects, once the snow melts!

Quote:

---

Originally Posted by FORBESAUTO

Attachment 369698

Hope this helps.

---

That image could be very helpful. When you're home would you be able to get me a better quality copy of the image.
Plus, if they have more than one diagram of the area, that would be helpful.

I have some good leads... so thank you, everyone.

Fuel is coming in but not going to the pulse pump? Elec pump? Is the hose barb for the bleed line under the carb hooked up?

That serial # is for like an 85 vertical front 150, which is what it looks like to me.

Oops I sent ya a horizontal. I'll have to see if I can find a vertical diagram.

I haven't tried to start it yet.

The hose barbs for the start up enrichener valve are all hooked up.
... by that, I mean the solenoid that opens when you press in the key before start up, which
opens a solenoid and allows fuel to flow into each carb in preparation for a cold start.

If that's what you mean by the "bleed line", then yes, it is fully hooked up.

The fuel pump is mechanical.

If there is a connection to the bottom of the air box, then that's my mystery line!!! Right now the air box is off.
When I'm next at the boat, I will check the airbox, and as soon as it warms up, I will take it to the ramp and try starting it up.
(Can't really run off the hose... it's too noisy for my neighbors) .

Quote:

---

Originally Posted by transomstand

That serial # is for like an 85 vertical front 150, which is what it looks like to me.

---

Thanks. This is all new to me.

I've had two V6's that were all of the mid 90's vintage, so I'm very familiar with that style.

This motor is the earlier style, that has a cowl that comes off in two pieces, and has
a lighter flywheel and a stator, etc for the lower (16 amp?) charging capacity. It's the design
that uses only 1 voltage regulator, while the mid 90's designs used 2.

OK. I've got it now!
@topgun marine was spot on when he wrote:

Quote:

---

Originally Posted by topgun marine

goes to the bottom of air box, if your not running the air block just plug it

---

@xtreamVking , I googled on "bleed line" and found some posts on an iboats forum that exactly matches my situation.

Attachment 369715


(quote)
Re: 1984 150 Black Max bleed line diagram

Your motor is a normal 5 line bleed system with a 6th vac line to air box.
Look at pic above only line missing is cyl#2 to carb/reed #5.All other lines are correct.
Ive got the same setup on my 88 V6 and diagram in service manual dated back to 1983.
Cylinder to Reed as follows.
c1-r4,c2-r5,c4-r1,c5-r2,c6-r3 plus fitting just left of r4 to airbox fitting.
(end quote)

and

(quote)
Rule of thumb. A bleed line goes from a reed block to the opposite cylinder in the firing order.
Vertical reed engines, reed blocks and fittings are directly in front of the cylinder it feeds.
Horizontal reed engines, the reed block is on the other side, feeds across the engine.

1 line is skipped on some engines.
(end qoute)

So I'm believe I'm good to go, and based on the description and the wiring of my bleed lines, the bleed lines from each cylinder all cross over
and go to a reed block on the opposite side...

Either that, or whoever had the boat before me really goofed... It wasn't running correctly when I got it,
so I won't take anything for granted!

(P.S. -- Wasn't sure if I should mention other boards on here... ScreamAndFly is my favorite... so I named the board, but didn't link to the info. I hope that's OK).

Thanks everyone! I now know that I have vertical reeds, and you guys have taught me that the "vacuum lines" as I was calling them
are really "bleed lines"... which made it easy to look them up and learn that the purpose is to suck excess oil out of the crank case,
which requires a one-way valve where the bleed line connects to the carb.

I never knew these engines could be so complicated... I guess I need to find a buy a mercury service manual. :-)

Sincerely,

-Philip

P.S. I also found this diagram on line in reference to a 1989 V6 150 w/ vertical reeds.
It agrees with the earlier images, it's just that this one was hand drawn.

Attachment 369718