Motor oil

[imported_dave j]

I am new to boating and have a question that is silly to most I am guessing. I understand differance between 2 and 4 stroke oils. But can you use conventional AUTOMOTIVE oil in a 4 stroke outboard motor? No where on conventional motor oil containers does it says for 4 stroke motors. Is it interchangable?

 

[tazrig]

Re: Motor oil

I am new to boating and have a question that is silly to most I am guessing. I understand differance between 2 and 4 stroke oils. But can you use conventional AUTOMOTIVE oil in a 4 stroke outboard motor? No where on conventional motor oil containers does it says for 4 stroke motors. Is it interchangable?

All automotive oil is 4 stroke, they don't print it on the container as that would be redundant. Automotive oil and marine oil is the same. The additives put into Marine oil are not. Additives to help control rusting and moisture in the oil among other things. Boat engines that are raw water cooled such as outboards run at a much cooler temp then car engines so they don't burn off as much moisture as a car engine would. Will your engine run on auto oil? Yes. If you want to baby it and have it for the longest period of time and have it be as trouble free as possible then use marine oil. Some auto oil manufactures also make oil for the marine environment. Look in your owners manual. So long as the oil you are looking to use is the proper viscosity and rating then you're fine. NOTE: There is a big difference in lower unit oil. Marine lower case oil is designed to mix with water and not separate (looks milky) if any water gets into your drive. This protects your lower gears. If you just run regular gear oil and water gets on your gears it can rust them causing eventual failure. Of course you should change your lower unit oil at least once at the end of every season (oil becomes acidic and contaminated over time so you don't want old oil sitting on your gears over the winter) AND after how ever many hours your manual recommends.

 

[Chris1956]

Re: Motor oil

Dave, 4 cycle outboards are run harder than automotive engines, due the the increased drag of the water in which they operate. To compensate, oil manufacturers have added a designation for oils suitable for 4 cycle outboards and I/Os. Look for a FC-W rated motor oil for your outboard.

 

[Bamaman1]

Re: Motor oil

When you have questions about any lubrication, you can look at BobIsTheOilGuy.com. They cover marine lubricants.

Many boaters use diesel oil, like Mobil Delo, in their 4 stroke outboards, including mega hour fishing fleets. But diesel oil cannot be used with any engine that has catalytic converters, like some of the new Mercruiser I/O's.

There's no marine oil that would be as good as regular Mobile 1 car/truck oil. They say it doesn't have the TC/W marine ratings. Mobil has never taken time to spend the money to undergo a very expensive battery of technical tests, as they're marine oil would be just a very small part of their sales.

 

[Chris1956]

Re: Motor oil

Bamaman, You do realize that a TC-W rating is for Two Cycle oil.

Also, why would you recommend Mobil 1 over the recommended FC-W rated motor oil? is that your opinion that Mobil 1 is better, or is there some analysis supporting it?

Automotive Motor oil has a completely different set of ratings. I have not looked recently, but Automotive motor oil used to be rated SG. That was some years ago and they update the rating often.