Synthetic oil in 4-stroke?

[TNAMBUSHER]

I recently serviced my small 4-stroke and used full synthetic oil in it. I had assumed that it was fine to use this type oil as long as it met the rating in the manual. I then saw on another site a discussion about oil and the concensus seemed to be that you should not use it in outboards. Does anyone here have any experience with this. I really don't want to drain the oil and change it if there is not an issue.

 

[stratos21xl]

Depends on the motor and the oil type. You should only use a "marine grade oil" in an outboard. Yamaha recommends full synthetic in all the SHO four-strokes.

 

[chillerman69]

more details on your motor and outboard would be helpful. If your outboard manual gave you a choice on synthetic and you took it, you should be fine. Something in your wording makes me think that you may have used something like Mobil 1. If you used an oil other than what you manual called for, you should consider changing it. Consider the oil cost vs. engine cost, it comes down, to why skimp. Outboards are hard running engines and deserve those few extra pennies and dollars, that the factory charges. Breaking down on the water is a great way to ruin a good day.

 

[churly]

I sell oil for a living. I get asked whats the best oil... My answer is always; if you use the correct spec, grade, amount, and change it at the manufacturers reccomended interval, you will never have an oil related issue. That applies accross the range of engine applications out there.

The difference between synthetic and conventional oil is; synthetic oil molecules are all very small and are the same size throughout the fluid. Thus, it moves easier, catches more trash and cools quicker, as opposed to convential, which contains molecules of various sizes. The engine manufacturers are being pushed to make cleaner burning, efficient motors by the fed. You will see everything is moving lighter synthetic oils for all engine applications

 

[TNAMBUSHER]

Thanks for the input guys. I called the Nissan service line and asked them about the oil. They sent me a list of "approved" oil for ALL 4 strokes. I drained the Castrol Edge and replaced it with Pennzoil Marine. Here is a link to the list in case anyone else needs to know.

http://www.nmma.org/certification/certification/oil/fc-w.aspx