I just bought a Snapper ST140, model 3312513BE with a B&S 12.5hp, model 286707-0136. I bought it cheap for a project. It starts and runs for about 5 minutes and then kills. The previous owner replaced the carburetor and the armature with no change in performance . The plug is fouled with black soot. Just turning the flywheel by hand I think the compression may not be and issue. I would appreciate any thoughts on what things I should check next.
