What engine oil should I use?
 

I've got a 21' boat with a Jasper Marine 350 in it. This is my first inboard/outboard boat. I've heard that straight 40W is the way to go. What about 15W40?

Dude. ;) I run sythetic, But that question is like asking
"what kind of beer do you drink?, and which one is better?" :D

You'll get 1,000,000 different answer. and they are all good answer. :rolleyes:

Run a good quality oil in the viscosity recommended by the engine manufacturer and youll be fine.

whaty does merc recommend for a 330hp 454????

Hey Puder,
They recommend you rebuild the ***** into a fire breathing 525 sc !!!
New crank, rods, pistons, cam, bearings, blower, heads, and exhaust!!!!!

Just kidding my brother!
I was going to run Mobil 1 synthetic
Did wonders for my trans am so I figured it would improve this tank of an engine as well
Might take 2-3 changes to completely wipe out all the natural oil and get lifters all pumped up wtih synthetic but hey, have to start somewhere

I run 20-50 in my engines
sometimes straight 50w
All synthetic.....RedLine Engines/trans/outdrives

OH NOOOOO!!!! Not another oil debate! :eek: :eek: :eek:

I'd stay away from the straight weight oil. Mercruiser recommends 15W40 for the small block (at least they did in 2000). I like to use Shell Rotella T. It's rated for heavy trucks, and exceeds all manufacturers' requirements. $5.99/gallon at Pep Boys! ;)

see what I mean :D :D :D :D

Run a quality oil and change it OFTEN. I usually run a 20-50 and am not totally sold on sythentics. So many choices. :rolleyes: