Engine Z425 John Deere twin cyl. 22 hp b/s

[goat roper]

Thought I had posted earlier, however, the second 22 hp JD briggs stratton engine has throwed craps in a matter of 4 years on a Z425. Is there an engine that will interchange besides the B/S that anyone has tried, like a kohler, kawasaki or anything besides a B/S?
Thanks for any input,
goat roper

 

[mechanic mark]

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