Sam I was hitting more on the maintenance side of the kt 17,and magnum 18 carb, plugs, ignition coil etc.. you have more experience inside the engine than I do. Also I find my experience mirrors J-Mech vanguard will not hold up to a magnum 18 in tall grass (way to tall and wet at that) my son also noticed this. The OP does need to check engine hours that was a good thing to hit on regardless of engine type.... also to the OP you have gotten a lot of great info on this thread I hope to see pics of a 682 right beside of your 1250
I didn't mean to come off as saying aluminum rear was an issue just not as good as the cast on your 1250. We are running 2 aluminum rears 1541, 1440 with zero issues.