FWA,
The info. below is out of the Strikemaster user manual:
Fuel
• Use unleaded regular, unleaded premium or non oxygenated premium fuel. Do not use fuel with less than an octane rating of 87. For peak performance use an unleaded premium fuel.
• Do not use leaded fuel or E85.
• FUEL MUST BE FRESH AND CLEAN. NEVER use fuel left over from last season or fuel that has been stored more than 30 days. Do not use summer blend fuel; only use winter blend fuel available after November 1st.
• Unsuitable fuel or deviations in mixing ratio may lead to serious engine damage which is not covered under warranty.