The trouble is we have very few options when it comes to engines on mowers. If I could of bought a briggs with the SZ, I would of. But no choice, had to get Kawi. I certainly wouldnt want another 31. Mine started leaking oil from the governor area and would/could of cost me a packet to repair it.
The 37 I have now doesnt use any oil (or very little) but its still young at 250hrs.
I used to use semi synthetic oil but now Im going to stick with dino and see if that helps keep the leaks to a minimum.