I have a Kawasaki FD440V on my John Deere mower. This is a 2 cylinder V-twin, liquid cooled engine. The label on the side of my engine specifies monograde 30 for temperatures above 32ºF.
I notice that when using a multigrade oil that my rate of consumption is a consideration. I have to check and top-off the sump after every 3 hour mowing session which I don't need when using monograde oils. In my Georgia climate (metro ATL) I use monograde 30 and it has worked well for my application for the past 20 years on this engine (don't remember exact purchase date).
As for oil filters, I have determined that the OEM JohnDeere filter that came on the engine was a Canadian made Fram PH4967,, painted black. The disection of the OEM filter and the Fram reveals that they are identical in construction, form and function. This Fram filter is applicable to an early 1990's Geo Prizm I think. The Fram costs a few dollars at the local Wal-Mart while the JohnDeere filter cost $8.
This combination of oil grade and filter choice has served me well for twenty years and I will continue this regimen. BTW, how did you bend a pushrod?