Replace the ignition coil and see if that solves it. A new ignition coil can be found online for less than $25. Here’s the diagnosis and install procedure.
I have a brand new Super Recycler (model 21386, SN 409164423) with a Briggs engine (model 104M020254F1, SN 2008191917003) that sputters while mowing. It started doing this the first time I mowed and appears to be a common problem among other owners. I contacted my local Toro dealer and they said...