What oil and oil filter do you use in your Mercruiser?

Serenity

Just thought I would get everyone's opinion. I own a 2005 320 with twin Mercruiser 5.0 MPI and Bravo 3 outdrives. They have about 230 hours on each motor. Mercury recommends using their 25/40 Synthetic Blend oil and their oil filter. I was wondering if there are other products which are the same or better. I have heard other boaters at my marina using 25/40 straight synthetic from companies like Mobil 1 and Penzoil with Fram oil filters. There is a large price difference but I do not want to save money and not do the right thing for my motors. Please let me know your opinions. thank you.

Babyboomer

I used Merc blend on my 7.4 had 1000 hours when I traded her she was still solid put around 75 hours a season and was down less than a half quart at end of season I always used the Mercruiser Racing filter on the 7.4 it was taller and could use a full 7 quarts of oil rather than 6.5 using standard short filter

Babyboomer

Marine certified Oils
https://www.nmma.org/certification/certification/oil/fc-w.aspx

Cableguy Greg

I use the Wix 51069 oil filter recommended by Al or the Merc hi-efficiency oil filter P/N 35-858004k. The oil that I use is the Merc 25W-40 synthetic blend. Not to knock on Fram filters, but I have heard bad things about them. If I wasn't going to use the Merc filter, I would use the Wix filter.

MarkB

Mercury semi synthetic oil as well as the mercury oil filter. 

rowboat212

It appears to me somebody is conjuring the sprit of MT.... 

Serenity

I had a feeling most use the Mercury products. I am sure I will stick with the 25/40 synthetic blend and Mercury filter. I have not had any issues but want to make sure I am giving the motors the best protection. I am going to contact Mercury regarding the taller Mercury Racing filter as babyboomer stated. I do not have the big blocks and it may be overkill but does not hurt to find out. If it is a few dollars more--it may be worth it for the added size to better filter the oil. Thank you all for your advise.

Babyboomer

Pretty Good write up on Filters in general there is probably no difference between Marine and Auto
http://www.minimopar.net/oilfilters/opinions.html

frenchship

Is it a big difference in using regular 25w40 mercruiser oil instead of synthetic blend since we changed oil after sometimes not even 100 hrs ?

JoeStang

I've used the Merc fully synthetic (just before it was dc'd), and this year I used Mobil 1 15w-50 fully synthetic.

I'm going to send in a sample for analysis to see how it held up for the ~ 50 hours of use, but it didnt burn a drop.

I use the Merc high efficiency / capacity filter too, since its only a couple bucks more and according to the chart on the box, it filters a LOT better.

Capt Ron

Merc oils have additives that auto oil doesn't use. For this reason I would stick with recommended oil and filters