Tecumseh 3 to 11 HP 4-Cycle L-Head Fuel

From Small Engine Wiki

Tecumseh strongly recommends the use of fresh clean unleaded regular gasoline in all engines. Unleaded gasoline burns cleaner, extends engine life and promotes better starting by reducing combustion chamber deposits.

[edit] Reformulated and Oxygenated Fuels

Reformulated fuels containing no more than 10% Ethanol, 15% MTBE, 15% ETBE or premium gasoline can bu used if unleaded regular gasoline is not available. Leaded fuel may be used in countries where unleaded fuel is not available. Never Use Fuel Containing Methanol.