Synthetic oil?

[flounder]

I have a 1988 OMC King Cobra with a 3.0 L 4 cyl motor. I am considering switching<br />to a synthetic oil but have heard both good and bad about doing so. My manual <br />says to run 30W oil in it. Any opinions on whether to go to synthetic or not and <br />what weight. I live in Ontario and use the boat in warm weather only.<br />Thanks

 

[FlyBoyMark]

Re: Synthetic oil?

Use 5W/50W pure synthetic Syntec Castrol.........If the engine has lots of hours on it and some small amounts of sludge it might NOT be a good idea to run synthetic. At this point it would not benifit the life span of the engine and because of the superior deterging action you could break loose the sludge that has foreign objects caught in it. Then again, if the engine only has a 100 hours or less on it , by all means use synthetic. It will reduce wear considerably on a new engine and really keep it clean. I speak from experince.......

 

[Scottj25]

Re: Synthetic oil?

Before switching you might want to check if the gasgets(?) are rated for this type of oil. I also have 3.0l/LX merc. with only 20 hrs. I've read alot of BBS and feel safe using the 25/40wt oil that is recommended. If you change the oil every 50 to 100 hours and filter you should be in good shape. After all the oil is the life blood of the engine and a oil/filter change is cheaper than a rebuild.

 

[shakespear]

Re: Synthetic oil?

Try F A Q on mercury's webb site it list all the latest recommedations<br />just a thought

 

[f_inscreenname]

Re: Synthetic oil?

In my I/O I was always told to run stright weight 30 because of the high rpm's.

 

[dhammann]

Re: Synthetic oil?

Synthetic oil will seep through gaskets made from cork or fiber. Why synthetic? I haven't heard of an epedemic of marine engines wearing out on conventional oil. Unless you use your boat on a daily basis the hull will rot out before you see enough hours to cause appreciable wear on the engine. In my opinion, use the tried and proven and factory recommended (both GM & Mercury)SAE oils and save youself some money and leaks.