MerCruiser Oil???

[wantacat]

Well, I put it in at 170 hours and it's at 183 now.
Basically, ask any engine builder, and they will tell you. A bearing doesn't know what the motor is in. Boat, car, truck, stationary pump. A boat motor is under some form of load at all times other than neutral. The better lube you throw at the metal-metal surfaces, the longer it will last.
Straight-weight oil is so "old school". 50's and 60's type stuff. I am real surprised that Merc still recommends that stuff with these "new technology" motors.
There is so much talk about oil it just drives me crazy. I think I'm just going to stick with mercury's 25w40 once I get my next oil change. If anything ever goes wrong, at least I can say I used the products they recommended. Also If you go ever to OSO.com everyone over there is using mobil 15w50, or straight 40 or 50. From kendall to mobile 1, redline etc. I guess everything works fine because there is so many people using different types of oil and seems like everyone is doing fine.

[Hollis]

Solec Publications certified Textbook and repair manual states use straight 40W in my Checkmate w/460...

[full throttle]

I run 40wt in natually aspirated motors, 50wt in turbo/blower motors.

[Thunderbutt]

Who do you think makes Mercury oil? Not Mercury!

[Beer-30]

I don't know who makes Quicksilver oils. That's a good question and now I am curious. I am sure it is just as good as the next. My only feeling on this is that Mercruiser has had these oils on the mkt since I was a boy. All these new GM motors are coming out with syn in them and void warr if syn is not used. (Vettes, Camaro SS, Firehawk, WS6). All have roller cams and are performance oriented. I feel the 496HO is a roller cammed high performance motor and deserves the same.
I agree there is so much talk of oils. Fact is, the engines will run as long at there is ANY oil in there. To each their own. I am an ASE certified mechanic in all aspects of automotive. It was a past career, now hobby. I am by no means an oil expert and I am surprised that someone that works for an oil company hasn't chimed in on these threads. If there is anyone on the boards like that.
The one thing nobody can deny is start-up. Straight 40 or 50 is pretty damn thick on start-up, regardless of warm outside temp. Friction tests on syns show how slippery and strong they are (don't break down as easy). If you have a pre-oiler on a motor, run 60wt if you want. 10-30 or 10-40 is gonna shoot into the passages faster on start-up. When I got the boat, it had 40 in it. Seemed like forever till the oil gauge would move. Now, it shoots right over to 60 as soon as it lights off. Since it is syn, it is stronger and slicker than the conventional 40 or 50. That's my take on it.
Run whatever you believe in. Mine is out of warranty anyway, so I feel I should put something in it to make it last as long as it can.