Penzoil vs. Mercruiser Oil for Outboard?

Mar 23, 2015
259
Catalina 22 MK-II Dillon, CO
I am changing the oil in my Yamaha 4 HP outboard. I have a bottle of Penzoil 10-30W oil in hand but the local marine dealer recommends the Mercruiser brand. Is there any real difference?
Thanks,
cec
 
Jul 7, 2004
8,402
Hunter 30T Cheney, KS
Probably because that is what he sells. Oil is oil. Just use the correct weight and rating.
 
Jun 2, 2004
3,390
Hunter 23.5 Fort Walton Yacht Club, Florida
There is a difference in the marine stuff vs automobile. Doubt there is significant difference between brands.

Anecdotally, a guy I knew who has a "Master" marine technician who's family owned a Mercury dealership and a marina grew literally up in the shop told me he always looked at the oil containers in the boat when they came in for work and never saw a blown motor with the marine Quicksilver, Yamalube, or whatever marine oil there were always automotive oil containers.

Walmart sells the Merc stuff and for as little as the small outboards use I've gone with the marine stuff.
 
Jan 18, 2016
782
Catalina 387 Dana Point
What would the difference be? Different additives? There must be a way to find out with actual data rather than anecdote if/what the real difference is.

 
Jun 2, 2004
3,390
Hunter 23.5 Fort Walton Yacht Club, Florida
Yes the additives as a boat motor typically runs cooler than a car and in a wet environment so there are additional corrosion inhibitors, other stuff too I don't remember now. I was going to switch to a full synthetic for our four coach boats in the youth sailing program at our club but after doing some research I decided to stick with the marine stuff. If I remember right I spoke with several sources and even to a guy with Mobile 1 and he suggested to stay with the marine stuff.
 
Mar 23, 2015
259
Catalina 22 MK-II Dillon, CO
Thanks to all for the comments. Sounds like a variety of opinions and I think the last post indicating that a FC-W rating is recommended cinched it for me. I actually don't know how old the bottle of Penzoil is and it does not have a FC-4 rating, so I will go with the Mercruiser brand for now. Better safe than sorry, especially since the engine does not take much oil!
 
Jul 7, 2004
8,402
Hunter 30T Cheney, KS
Thanks to all for the comments. Sounds like a variety of opinions and I think the last post indicating that a FC-W rating is recommended cinched it for me. I actually don't know how old the bottle of Penzoil is and it does not have a FC-4 rating, so I will go with the Mercruiser brand for now. Better safe than sorry, especially since the engine does not take much oil!
That's how to look at it. Viscosity and rating are what matter. For the little that is needed, if Mercruiser gives piece of mind it's worth it.