I've used Mobil 1 with good results as well, funny thign, if you read the fine print in the Mercruiser Warranty(not sure about Mercury OB) they do NOT recomend synthetic engine oil and will NOT cover any warranty failure due to its use. That being said, I still think Mobil 1 is a great oil. I used to run it in my 72, when I would first change the oil, the oil pressure would stay up around 40 psi at idle, after about a week of hard driving, the oil pressure would drop to around 20 psi at idle. we were using Mobil 1 in the 2 speed gearboxes on the sweepers, I contacted teh Mobil engeneers thru our company guys, they told me the oil is made in one viscocity, they add viscocity enhancers to create multiple oil rateings for marketing purposes. the viscocity enhancers breack down pretty quick, but the oil still does what its supposed to. Now a days its not uncommon to see 0-5 weight oil being recomended, and plenty of oil manufactures making it. They did tell me not to run Mobil 1 in any engine that use oil pressure to operate vital functions, like the 7.3 International that uses high oil pressure to fire the injectors
|