Join Date: Sep 2012
Location: Bremerton, Washington
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Re: Confused about which oil weight to use
Posted a similar thread on "Bob is the Oil Guy". Amazing how varied the responses have been.
One correction to my original post: Here is what the manual actually calls for:
<50F: 10 or 20 weight
50F - 60F: 20 weight
60F - 95F: 30 or 40 weight
>95F: 50 weight
Based on my research, and forum responses that seem well reasoned, I need an oil with an hot viscosity of 40 or 50, and a cold viscosity as low as possible (for ease of starting and initial start flow). Something like 15w40 in conventional, or 5w40 in synthetic. Pretty much confirms what most people recommend.
1981 Spirit 28 "Bonnie Lass"