What oil to use

[Chonk]

I recently purchased my first boat, a 1989 SeaRay 160 BR with a 3.0L Mercruiser Alpha 1.

Of course the boat came with no manuals.

I am going to purchase one from Mercury, but until then, what oil should I use? Can you use an automotive oil?

 

[Eric 3.7LX Alpha 1]

Re: What oil to use

You can do a search on it in this forum. (best thing to do cause it's been covered so many times already).

There's about a gazillion threads on oil and what everyone here uses and hates. Ask something like that and your gonna get about 200 different answers.

http://forums.iboats.com/showthread.php?t=426361

http://forums.iboats.com/showthread.php?t=409096

http://forums.iboats.com/showthread.php?t=423766

http://forums.iboats.com/showthread.php?t=423660

http://forums.iboats.com/showthread.php?t=415140

http://forums.iboats.com/showthread.php?t=421856

http://forums.iboats.com/showthread.php?t=421125

there's over 130 responses in those threads for you to read.

 

[achris]

Re: What oil to use

From the Merc manual....

Now, what I use is Diesel engine oil, 15W-40. The loads on a boat engine are closer to that of a truck engine then a car engine. Most diesel engine oils have a petrol engine rating too, so the additive package is the same, but with better shear load capabilities. I change oil every 50 hours, and filter every 100hours..... Just my 2c worth....

Chris.........

 

[Don S]

Re: What oil to use

Use whatever oil you want. It doesn't even matter.
Marine engines do not live or die because of the type oil used.
They die because of lack of maintenance, lack of use, or water intrusion (usually because of lack of maintenance)
Even the cheapest oil found has been used by someone, somewhere and they swear it's the best thing since sliced bread.

It's such a non issue that Mercruiser won't even address what to use in their own website.
Have a look.
http://www.mercurymarine.com/servic...ntenance/faqs/mercruiser/?category=fuel#MCOil

 

[myoldboat2]

Re: What oil to use

From another thread quoting Merc's recommendation:

NOTE: The use of non-detergent oils, multi-viscosity oils (other than as specified), non-FC-W rated synthetic oils, low quality oils or oils that contain solid additives are specifically not recommended.

This crankcase oil recommendation supersedes all previously printed crankcase oil recommendations for MerCruiser gasoline engines. The reason for this change is to include the newer engine oils that are now available in the recommendation.

Over the years, I've been spending my money on the Merc/Quicksilver 25W-40. I've had good results, but as Don said, it's about maintenance, not which oil. Because I never use this boat below 60 degF, I think I'm going to switch to SuperTech SAE40W, because it's a straight 40 that meets the engineering spec, meets the Mercruiser spec, and is readily available and inexpensive at Wallyworld--so I can buy it almost anywhere. We put less than 60 hours a year on the boat (short Midwest season) and I change the oil & filter every year.