4 stroke synthetic oil?

[finger]

i have a new, to me, 4 stroke 1999 50 hp. The place i bought it at changed the oil and used synthetic oil in it, but i forgot to ask what he used.

Do i need to use merc 4 stoke oil or will any 4 stroke oil be fine?

AND/OR..

very newbish question...

what is the difference between 4stroke synthetic marine oil and regular automotive synthetic oil, can i use good quality automotive synthetic in the OB?

thanks

 

[Silvertip]

Re: 4 stroke synthetic oil?

Most manufacturers recommend FCW branded oil. In other words the container will have the symbol "FCW" on it. Suzuki is much more lenient in its oil recommendations.

 

[finger]

Re: 4 stroke synthetic oil?

Most manufacturers recommend FCW branded oil. In other words the container will have the symbol "FCW" on it. Suzuki is much more lenient in its oil recommendations.

So any motor oil will be fine as long as it has FCW on it?

Does automotive synthetic generally have FCW, or just some brands?

 

[john3497]

Re: 4 stroke synthetic oil?

FCW - Four Cycle, Water cooled

If I'm not mistaken. Cars are both four cycle and (mostly) water cooled, so it must be the "marine" additives that make up the difference

Other post on Automotive oil:
http://forums.iboats.com/showthread.php?t=376652

 

[Silvertip]

Re: 4 stroke synthetic oil?

Not many 25W-40 auto oils around and they are specified with API ratings. Can you say check the user manual or the Merc web site for oil recommendations. The filler cap on the engine may also tell you that. As I said, my Suzy uses 10W-40 API or FCW so that would iinclude either auto or marine specific oil (conventional or synthetic). Because it has synthetic in it now does not mean you need to use it next time. The motor doesn't care.