Model 126T02-0301 B1 10030158 Charity work. Troy built pressure washer, pump removed, Briggs series 675, built around 2010. New pump to be installed after engine is satisfactory. Found loose head bolts, alot of carbon, could spin valves easily. Head pitted more than I have ever seen. Intake valve seal shot. Original complaint was start then die. Replaced carb, seal etc. Lapped valves, ensured proper clearance (.006/.008). The intake seat appeared not quite square or seated evenly in head but assumed it is ok. Did not do rings, no ridge but a few scratches noted. May do rings if I can determine oversize or not and worth it? Engine started right up. A little sputter about every 3-5 seconds though. Also I think the engine runs mechanically rough, like something unbalanced attached to it. But others didnt notice, just amazed it ran. Please advise or opinion? Thanks for your time and understanding.