The owners' manual for my 2001 Mercury 4-stroke (90) does not indicate
how to drain the crankcase oil. How do you do that?

Is is really important to use Mercury Quicksilver oil as opposed to
Valvoline or other quality products?

Look for a drain plug on the side of the leg. Tilt the engine to the trailer
position , rotate the motor until the drain plug is facing down, remove
drain plug.
That's the process for my 60hp Merc, should be pretty close for your 90hp.
There has been a lot of discussion about whether the engine manufacturer's
branded oil is better than independent makers. My manual recommends Mercury
or Quicksilver 10W-30, but says that you can use any API certified oil that
meets any or all of these specifications: SH,SG,SF,CF-4,CE,CD,or CDII.

"A.Z" wrote in message
om...
The owners' manual for my 2001 Mercury 4-stroke (90) does not indicate
how to drain the crankcase oil. How do you do that?

Is is really important to use Mercury Quicksilver oil as opposed to
Valvoline or other quality products?

If you want a better oil for your engine, try one of the synthetics. Mobil
1 can be purchased off the shelf at most stores -- Meijer, Walmart, etc.
For even better oil, try Amsoil or Redline. You would need to find a dealer
(local person) or order direct online. For me, I would probably go the
Mobil 1 route since it is readily available. For my 60HP Mercury 2 cycle, I
have switched from Mercury to Amsoil. My neighbor has become a dealer so it
is relatively easy for me to obtain that oil now.

Jeff


"A.Z" wrote in message
om...
The owners' manual for my 2001 Mercury 4-stroke (90) does not indicate
how to drain the crankcase oil. How do you do that?

Is is really important to use Mercury Quicksilver oil as opposed to
Valvoline or other quality products?

Tilt the engine to the trailer
position, rotate the motor until the drain plug is facing down, remove
drain plug.

That is a very important step. My engine was "making oil" for over a year
before the second dealer I went to told me this is a known problem. Oil hangs
up in the pistons and other nooks and crannies in the motor. If you tilt it up
and let the engine drain, then tilt it down all the oil comes out and you can
get the 3 quarts in without overfilling.

"A.Z" wrote in message
om...
The owners' manual for my 2001 Mercury 4-stroke (90) does not indicate
how to drain the crankcase oil. How do you do that?


On my 50 Hp Mercury outboards the crankcase oil has to be sucked out the
dipstick tube. The tube has a male hose thread on it so you can easily
attach the hose from a hand pump and suck the oil out.

Rod

Rod McInnis wrote:
"A.Z" wrote in message
om...

The owners' manual for my 2001 Mercury 4-stroke (90) does not indicate
how to drain the crankcase oil. How do you do that?



On my 50 Hp Mercury outboards the crankcase oil has to be sucked out the
dipstick tube. The tube has a male hose thread on it so you can easily
attach the hose from a hand pump and suck the oil out.

Rod

The owner's manual for my 2001 Mercury 30 4-stroke covers both methods,
i.e. tilt and remove drain plug, or pump out the way it went in.

Any opinions on which method is preferable? (I haven't had to do it yet
- motor has only been in service a month despite model year).

Sunny