4-Stroke Oil

[Dencope]

Hey guys, just doing an oil change on my 1998 9.9HP four stroke kicker. I have some expensive Castrol Edge SAE 5W-30 full synthetic. Would anybody recomend or not recomend using that in my kicker? I do not know what kind of oil was used in it previously as it is a new motor to me. Thanks in advance for any advice.

 

[SpringFever552]

Hey guys, just doing an oil change on my 1998 9.9HP four stroke kicker. I have some expensive Castrol Edge SAE 5W-30 full synthetic. Would anybody recomend or not recomend using that in my kicker? I do not know what kind of oil was used in it previously as it is a new motor to me. Thanks in advance for any advice.

I'd say your safe but dont take my word for it..
I use 10-30 full synthetic in my 9.9merc kicker under warranty for 5 more yrs

25-40 synthetic blend in my 357 merc(chev) inboard under warranty for 1 more yr

 

[Wild Bill]

What I have been told by some marine guys I really respect is:
First of all 5W/30 starts with a 5 weight oil and added friction modifiers react to heat and thicken the viscosity.
When you shut the engine off 5W/30 will leave a thinner protective layer against corrosion from humidity than say a 15w/40 or say a straight 30 weight oil. The thicker the protective layer the better in a marine environment.
Castrol and their synthetics are my go to!