On Wed, 06 Oct 2004 05:40:04 GMT, 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?

Karen has pretty much hit it. Straight 40 weight if that's what the
manufacturer recommends.

However, you might want to discuss with him the age of the motor and
if it's lasted this long on the 30/40 combination, then why not stick
with it?

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