Prepping for oil change on a '98...

[Tung]

Prepping for oil change on a '98 270 Dancer and looking for recommendations on oil brands/weight for Mercruiser 7.4MPI. I tend to think of this as a engine and leaning towards a decent synthetic oil as to not break the bank. Any thoughts to share?

[Tung]

I meant "I tend to think of this as a standard engine"

[wingless]

Welcome to the forum.

My preference is the Mercuiser SAE 25W-40 synthetic oil and Mercruiser oil filters.

https://www.amazon.com/QuickSilver-8M0078623-Stroke-Synthetic-25W-40/dp/B00FM9AVKI/ref=sr_1_4?dchild=1&keywords=mercruiser+engine+oil+synthetic+gallon&qid=1619633197&sr=8-4

[Carol_s_Cruiser]

Ditto!

[Tung]

Thank you wingless and Carol's for the oil insights. I'll give Mercruiser SAE 25W-40 a go.

[MrB18]

Hi Tung, been using Royal Purple 10W-40W for many years, incleased fuel mileage and in years when only had 50 hours or so skiped the oil change and just changed the filters. Oil has always looked great when drained for an oil change. Worth the $9.00 a quart!

[Tung]

Thanks MrB. will def look in to Royal Purple

[PJS]

How about checking the owners manual that lists the approved replacement fluids for that engine package? The internet has lost of information, just requires effort.

[Tung]

I have referenced a digital copy of the manual for this vessel and although the is detail in terms of components, it seems to be lacking in maintenance detail. I do not see an outline of recommended fluids in this copy. The problem with the internet is that there is an over abundance of information and not necessarily correct information at that. What I was looking for in this forum was practical first-hand experience from users as opposed to marketing and promo. Additionally, there are more options available today then there was in 1998 and so nice to get updated information inclusive of these "newer" options.

[wingless]

@Tung Kieu The Sea Ray Owner's Manual and Supplement are only one part of the total documentation required for ownership and maintenance on the boat.

In my case, I have a completely full suitcase file carrier, plus a tall stack of manuals, just for the printed documentation for this boat. I also have many, many electronic files of documentation. My preference is to have both, w/ the hard copy always on board the boat.

WRT to your inquiry and observations, many of the fluids are for the engines / transmissions and are covered in the correct Mercury Factory Service Manual (FSM). The Mercury Mercruiser Service Manual 23 covers the 7.4L in all configurations and the 8.2L. It includes maintenance fluids.

There may be more current manual options. This one was copyright 1999.

Back to the overall manuals, I have manuals for all the systems on the boat, including things like steering, trim tabs, electronics, A/C, Vacuflush, windlass, the list goes on and on... None are covered in the Sea Ray manual, except to say they exist and to show the switches and breakers, as appropriate.

[PJS]

Yes, that is the point. Everyone has an opinion, does not make them all correct. The engine manufacturer provided best recommended specs for fluids. Would you rather go with someone's "advise" because it works for them and potentially have problems or go with what the manufacturer publishes and requires for warranty (assuming the mechanical component is covered). It took me a whole 2 minutes to pull up the Mercruiser manual that lists the recommended fluids... Whenever I have a question my first move is to go to the manufacturer resources, and there are widely available, and take the time to learn...

[Tung]

point taken

[Tung]

and thanks for the attached specs. appreciate the help

[Stu2]

Pjs is correct in using mercruiser recommended oils. The problem is the recommended oil is no longer available. So you need to determine if your engine uses a flat tappet cam or a roller tappet unit. The year of manufacture is right about the change over time by the engine manufacturer. Please let the list know so we can help you find the correct product.

[Johnny_P]

Boat owners come here for quick answers to simple and sometimes difficult questions from knowledgeable owners. This is a great way to connect with that group. No question should ever be considered small, especially from new and inexperienced owners.