Mixing oil weights is a NO,NO.
SAE30
If it is a Briggs engine it takes SAE30. If it is a Kohler engine it takes 10W-30.
Check the owners manual on the web for your product, for example the F200 series specifies the same oil as the engine SAE30
If it has a Briggs and Stratton engine you need SAE30. If it is a Kohler it uses 10W30.
It is a little thick. You should use sae30 or 10w30 (on cold temperature)
SAE30
If it is a 4-cycle engine you definitely need motor oil. If its a 2-cycle engine then the oil is mixed with the gas. If its a reel mower then no oil is needed except for external lubrication. Depending on the engine manufacturer the 4-cycle engines will require either SAE30 or 10w30 motor oil.
SAE30
sae30
The higher the number the higher the viscosity.
SAE30