It is generally not recommended to use a different viscosity oil than what is specified by the manufacturer for your Honda lawn mower. The oil viscosity, such as 5W30 or 10W30, is specifically chosen to provide optimal lubrication and protection for the engine under varying temperature conditions.
Using a different viscosity oil can potentially affect the engine's performance and longevity. In particular, using a thinner oil (such as 5W30 instead of 10W30) may not provide sufficient lubrication at higher temperatures, leading to increased engine wear and potential damage.
To ensure the best performance and longevity of your Honda lawn mower's engine, it is advisable to follow the manufacturer's recommended oil viscosity as stated in the owner's manual or consult with a Honda authorized dealer for specific guidance.