On the bottom of the lower unit near the skag you will find an oil plug,
this is to fill/drain the unit. The two plugs you mentioned up higher: The
lower one is to vent the lower unit while filling/draining, the other is to
drain water from the water pump housing.

You might want to consider mixing gas and oil at a ratio of one bottle of
Merk oil to 5 gallons of gas. The bottle will tell you to mix one bottle
with 6 gallons of gas. I always mix it heavy on oil, spark plugs are a lot
easier to change than pistons and crankshafts. I have never had any
problems with this heavier mix, Merk oil burns clean and leaves only a
slight residue in the cylinders, usually it can be wiped out with a cloth
during a tear down after 30 years of hard use!

Meks oil injection has not been the most successful thing they ever did and
a lot of motors have burned up because of it. By using gas/oil mix you
eliminate that risk totally.

The carbs have a screen filter in the cap where the fuel lines attach. An
external water separating fuel filter between the tank and the motor is a
good idea.

Don Dando


wrote in message
oups.com...
My second hand boat comes with a 1995 Mercury 115-hp 2-stroke outboard
motor. Unfortunately, the boat doesn't come with an owner manual and I
don't know when the manufacturer will mail the owner manual to me. I
need some info about maintaining this motor:

- It is a 2-stroke motor with oil-injection (this means oil is not
mixed with fuel in the tank). I cannot find anything that looks like
an oil filter. Is this normal?

- Do I expect to see a fuel filter somewhere to trap water in the
fuel? Is it a good idea to retrofit a fuel filter to the fuel line if
the fuel system doesn't come with a fuel filter?

- I am trying to locate the screw hole for draining engine oil from
the lower part of the outboard motor. I can see two screws in the
right side of the lower part of the outboard. They are a couple inches
apart, and one is above the other by an inch. Which one is the one
that I should unscrew in order to drain oil from the lower part of the
motor? Where is the vent hole for draining oil?

Thanks in advance for any info.

Jay Chan