My newly acquired LB 7080 ser. 5950878 says 1/2 pint per gal. on the motor. Researching the mower, various sites say 32:1. Could this mower have a "transition " motor from 1969? One source says its a D-431, other says D-432. Is there a difference? Newbie to vintage LB's needs help. BTW, my free...