Oil dilemma -- Need advice please.
 

My boat has twin 525SC's....
they have about 420 hours on them. (yes, they are being freshened up soon.) I am going to change the oil for the first time since I bought this a couple months ago and was doing some research.
1) Previous owner ran Mobil 1 15w-50 full synthetic.
2) Owner before him ran Mobil 1 20w-50 full synthetic.
3) A very competent mechanic at LOTO said " Mercury recomends that the only blended oil you run is Mercury's blended oil (15w-40) if you don't use mercury's blended oil then they recomend straight 40 weight." He also said that full synthetic is a waste of money that I should get it all out and go to regular oil because even though the increased wear on a boat motor vs. a car.... a full synthetic is overkill as it is meant to last a really long time and doesnt hardly break down.

So all that being said, I am kinda leary on what I should run in here. Stick with the same that is in there? The oil actually still looks pretty good. Is there really much difference between that 40w or 50w in the blended which I understand comes into play after the oil gets hot.

Would like to hear what you all think and what you all run or would run if you had my ride. Thanks fellas!

There is a huge thread on this topic here --> http://www.offshoreonly.com/forums/s...d.php?t=107808

Bottom line, the oils the previous owners were using were a couple of the best choices to make.

I've used the Mobil 15/50 for quite a few years. Last year (after new engines) my builder wanted me to use Valvoline straight 40 weight. I change the oil every 25 hours so I don't think any of them are a bad choice.

Thanks t500hps....
I wonder why your mechanic/builder wanted you to switch?

I did some research and it seems that the M1 15w-50 is a popular oil , and it seems I cant really go wrong with it. Just trying to be extra cautious with my baby... There are acouple previous owners to her that would be upset with me if I was any less cautious. ;)

Stick with the Mobil 1 15-50 synthetic. I ran it in my 525SC as did the prior owner. It was run from at least the time it had 100hrs on the engine. The engine now has over 500hrs on the bottom end. In the 5qt jugs at Walmart, its only a little more money than good conventional oil.

My only question to Merc would be WHY??????...................maybe because their oil makes them $$$$$.

Thanks Griff....

Yeah, that was response when I heard that but he swore it wasnt about that - more that the "blend" was specific to their own motors, blah blah... bu in the end, of course they will only recomend their own stuff.

Thanks again pal....:ernaehrung004:

read the marine lube posts indicated above if you have the time, if I can shorten hours of reading-mobil 1 ep silver cap is very good, the mobil 1 V-twin is much better-about twice the price of ep (v-twin designed for v-twin motorcycles & not have to worry about hurting catylatic converters & has more lubricants called zddp (zinc) & phosporous (?). also the boys say top end redline, amsoil, & royal purple are great also. It seems that sterling engines liked mobile 1 syn-I would think their vested interest is in protecting their product.

Thanks for the info Jaimie.... I appreciate it. I am going to stick with the M1 EP....

Based on the thread mentioned above (marine lubrication) I run 20w50 V twin Mobil 1 in my 525sc, no problems so far. It is expensive, but what isn't on a boat. (and a WIX 1060R filter)

I would just use the silver cap in the Jugs. It is the old red cap formula, I believe. The EP/gold cap only comes in quarts and cost 50% more.