WaIIy wrote:
I have Mercruiser 5.7's 1989 and boat on Lake Erie near Cleveland.
My mechanic recommends straight 30wt oil and that's been fine, today he
said a new bulletin came out from Mercury and it was something like 30
wt up to 60 degrees F and 40 wt for over 60 degrees F.

Now my mechanic says to use straight 40 weight.

What do you think?


Mercury recommends 25W-40 oil for Mercruiser engines, back in '89 they
rcommended straight 30 weight. In '89 Mercury sold 30 weight and warned
against multi-viscosity oils, now they recommend and sell it.

On Wed, 06 Oct 2004 09:20:34 -0400, John Wentworth
wrote:

WaIIy wrote:
I have Mercruiser 5.7's 1989 and boat on Lake Erie near Cleveland.
My mechanic recommends straight 30wt oil and that's been fine, today he
said a new bulletin came out from Mercury and it was something like 30
wt up to 60 degrees F and 40 wt for over 60 degrees F.

Now my mechanic says to use straight 40 weight.

What do you think?


Mercury recommends 25W-40 oil for Mercruiser engines, back in '89 they
rcommended straight 30 weight. In '89 Mercury sold 30 weight and warned
against multi-viscosity oils, now they recommend and sell it.

Which brings up another guestion.

On two cycle engines, the TC-W3 standard (I hope I have that right) is
the "standard" to which all engine are supposed to be built, right?

Then why do the various manufacturers all consider non-factory oil a
bad thing?

Later,

Tom
-----------
"Angling may be said to be so
like the mathematics that it
can never be fully learnt..."

Izaak Walton "The Compleat Angler", 1653

"John Wentworth" wrote in message
...

Mercury recommends 25W-40 oil for Mercruiser engines, back in '89 they
rcommended straight 30 weight. In '89 Mercury sold 30 weight and warned
against multi-viscosity oils, now they recommend and sell it.

That's a good BINGO.
-Dano

John Wentworth wrote in message ...
WaIIy wrote:

Mercury recommends 25W-40 oil for Mercruiser engines, back in '89 they
rcommended straight 30 weight. In '89 Mercury sold 30 weight and warned
against multi-viscosity oils, now they recommend and sell it.

Interesting, but I am doubtful. I installed 2 new mercruiser 5.7 liter
I/Os in year 2000. The owners manual specified their own 25w-40 with
other multivis as alternatives. It specifically recommended against
synthetic oils. That seemed weird, so I called my friend who has a
1985 mercruiser 5.7 liter I/O. His owners manual was identical in all
respects about oil except it did not say anything about synthetic oil.
Somewhere between 1985 and 2000 Mercury saw fit to add one sentence to
the manual to recommend against synthetics. Neither manual listed
straight weight as a first or second option.

Bob wrote:
John Wentworth wrote in message ...

WaIIy wrote:

Mercury recommends 25W-40 oil for Mercruiser engines, back in '89 they
rcommended straight 30 weight. In '89 Mercury sold 30 weight and warned
against multi-viscosity oils, now they recommend and sell it.


Interesting, but I am doubtful. I installed 2 new mercruiser 5.7 liter
I/Os in year 2000. The owners manual specified their own 25w-40 with
other multivis as alternatives. It specifically recommended against
synthetic oils. That seemed weird, so I called my friend who has a
1985 mercruiser 5.7 liter I/O. His owners manual was identical in all
respects about oil except it did not say anything about synthetic oil.
Somewhere between 1985 and 2000 Mercury saw fit to add one sentence to
the manual to recommend against synthetics. Neither manual listed
straight weight as a first or second option.


In a Mercury Marine service manual I have that covers the early '80's
the recommendation is:
Lowest temp is 90°= SAE 40 "SE"
Lowest temp is 32°= SAE 30 "SE"
Lowest temp is 0°= SAE 20W "SE"

For much of the United States that equals SAE 30, oil to be changed
every 100 hours or 60 days, whichever comes first.

Also: " We recommend Mercury Marine 4-Cycle Marine Motor Oil Formula 4R.
If not available, use any good grade automotive oil of correct viscosity
which has an API classification of "SE".


One thing for sure, the topic "Oil for my boat" will produce a deluge of
responses. Can a "dead reckoning" topic be far away?

On Thu, 07 Oct 2004 09:13:28 -0400, John Wentworth
wrote:

~~ snippage ~~

One thing for sure, the topic "Oil for my boat" will produce a deluge of
responses. Can a "dead reckoning" topic be far away?

Kewl!!!!

All the best,

Tom
--------------

"What the hell's the deal with this newsgroup...
is there a computer terminal in the day room of
some looney bin somewhere?"

Bilgeman - circa 2004

"Bob" wrote in message
m...
Interesting, but I am doubtful. I installed 2 new mercruiser 5.7 liter
I/Os in year 2000. The owners manual specified their own 25w-40 with
other multivis as alternatives. It specifically recommended against
synthetic oils. That seemed weird, so I called my friend who has a
1985 mercruiser 5.7 liter I/O. His owners manual was identical in all
respects about oil except it did not say anything about synthetic oil.
Somewhere between 1985 and 2000 Mercury saw fit to add one sentence to
the manual to recommend against synthetics. Neither manual listed
straight weight as a first or second option.

From my 1987 Mercruiser Blue Water Inboards Operation and Maintenance Manual
(260hp)

"IMPORTANT: The use of multi-viscosity oils specifically is not recommended
for use in MerCruiser Engines." Then follows a chart that recommends SAE
20, 30 or 40 depending on temperature. There is no mention of synthetics in
this manual.-Dano

I just today put Amsoil 15-40 marine diesel in that 1987 260 hp 5.7
Mercruiser as I have been doing for a couple years now. I'll know in
2500 hours whether it was a good move or not!

Capt. Jeff