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Old 06-16-2022, 03:58 PM
Sam Sam is offline
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I too have never added MMO to oil, fuel yes - oil no. I have had for the last 45yrs a 1966 early model that has never needed rebuilding. It is a short season in Chicago and I usually clock about 25 to 30hrs a year engine time with the longest run being about 6 hrs each way to and from yard ...a lot of shorter runs entering/leaving harbor. I was an engineer and not a chemist but recommend and do change oil mid season and just prior to haul out for winter layup. I use any quality 4qts 10w-30 or 30 with some STP added at spring launch. My layman's understanding from an old mechanic friend is that besides some viscosity thickening it contains extra zinc which aids in improving lubricity and resists corrosion. Oil pressure at start up is about 45psi and settles down to about 35psi and about 25psi at idle. To some [and manual] this may sound a little wasteful but for about an extra $15 and half hr of time I like the idea of clean oil in a non filtered engine. Just my thoughts- hope this helps.
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