4-STROKE SYNTHETIC ENGINE OIL

[SeaDawg]

Fellas, does anyone have advice about Castrol Syntec engine oil for 4-stroke outboards? I ran it for several years in Honda 15 and 25 HP engines, and the Honda rep said it was fine to do so.<br /><br />But I know the Mercury and others 4-stroke oils have anti-foaming agents.<br /><br />I just got a used Mariner 50 HP 4-stroke this past winter, and don't want to go to synthetic oil until I get some reassurance.

 

[SeaDawg]

Re: 4-STROKE SYNTHETIC ENGINE OIL

bump

 

[Walt T]

Re: 4-STROKE SYNTHETIC ENGINE OIL

Synthetic oil has excellent anti foaming additives, in fact nearly all four stroke oil does.

 

[RJS]

Re: 4-STROKE SYNTHETIC ENGINE OIL

The primary advantage to synthetics is viscoelatic properties at temperature extremes. Outboards run cool in comparison to automotive engines. Moisture is the biggest enemy to your engine. Synthetics have no inherent advantage to mineral based oils in this area. The key factor is to make sure that that oil is marine grade (natural or synthetic)so that it has the proper additives to deal with moisture. You probably can't go wrong if you stick with the oil recommended by the manufacturer of your engine. If you run your engine hard (racing, high RPMs, or in very cold water), you may want to go with the synthetics.