I Just looked in the book for our 7FGU25 and it recommends SAE40 or 30 but does have the temps listed right 86 and above for 40w, 32 to 86 for 30w, and 20w for 14-32 degrees F.  I guess we have always ran 10w30 in ours now problems so far. Our is kept in heated shop in winter so doesn't have to cold start.