I put a 12hp fb stratton synchro bal m 283707 t 013401 c 9505104d electric start on an old rear engine rider! the 12 came on my snapper tractor the rer has a 8hp bs pull start dont know its age but had to cut of a fender the get the motor to fit! it runs fine Im about 90% happy with it! The one problem is the 12 has a square muffler on the it blows to the side but in the first few mins about 10 mins of running it heated up my switch to almost untouchable! so I modified a can cut it put a hole in the side and clamped it to the round part of the muffler it works . I cut my yard about 1.5 hrs and when I stopped it was hot but not hot enough to melt the wires or hurt anything ! but its a lot louder now and Im wondering if it will hurt the engine! this was meant as a temporary fix but Ive been hunting all day for a regular muffler that bolts on and afixs to the side of the engine but Im having no luck finding one with my modle # will any 12hp briggs muffler work on my motor thanks for the help