What oil to use?

[sambluckie]

I have a 1985 Wellcraft with the 3.7 litre MerCruiser engine. The owners manual specifically states not to use multi-viscosity oil. The original owner only used Mercury 30 wt oil. I am having a hard time finding Mercury 30wt oil anywhere. Would it be OK to use a multi-viscosity such as 10w40? Only had the boat a few weeks. Seems to be well taken care of and runs great. I would like to keep it that way.

 

[guyaverage]

Re: What oil to use?

In the last decade with my 470, I have run various brands of straight 30wt, 40wt, 10w-40, 15w-50, 20w-50, and most recently 15w-40. The 40wt I got at the local chain auto parts store, the rest of these were all available at walmart.

 

[Oshkosh1]

Re: What oil to use?

The dreaded oil thread...

I'm channeling my inner Marlon Brando...

"The horror...the horror...the horror"

Shell Rotella 30Wt is as good as it gets...and about $13 per gallon.
Spend the savings on a good Wix made filter. The Napa Gold is made by them, along with the premium Carquest line I believe.

 

[sharkin95]

Re: What oil to use?

Walmart has both 30wt merc oil $6.59 qt. and 25-50 $ 6.39 qt I personally use pennzoil 10-40 change it every year on my 4.3 v6, the recomendation on the valve covers are 30wt.

 

[achris]

Re: What oil to use?

Well, I'll stick my 2c worth in.... I use 15W-40 DIESEL engine oil.... Have done on this and my previous engine (still do on the previous engine as I still get to service it. And it's 18 years old..... )

Chris.........

 

[wrestling coach]

Re: What oil to use?

15w-50 Mobil 1 in my '83 470 here with a Baldwin filter.

Dennis