I have an old Firestone 10 I'm wanting to try and get a little information on. It's serial number is 18353541 and the code number is 133-3-1835 stock number is 10-a-104 does anybody know what year this motor is? Also, what is the oil mixture on it? It says 1/2 pint of sae 30 oil to one gallon of gas. Is this just regular motor oil?