3.5hp briggs oopsie--help


Active Member
Local time
11:44 PM
Dec 18, 2021
Lancaster Motor Speedway SC
ive got a good ole reliable 3.5hp briggs, that i took month of my life trying to aquire, and now it wont make putt putt noises anymore. i was turning about 4000 rpms, (ive beat it harder, for longer, i was going fairly easy), whipping a donut in a grassy field, when it died. has a 3/4 tank of fuel. it would try every 15 pulls on full choke. i have a new diaphragm. nothing. i took it apart, put another new diaphragm in it, cleaned all passages, cleaned fuel strainer, checked if the cam was timed fine, nothing. only runs on carb cleaner. new fuel, nothing. Im at my wits end. the only thing i can think of, is if the spring is out of spec. i need to measure it. my briggs maunal has the specs. the only other thing i can think of, is the head gasket, but it seems fine, from my small inspection. i cant read any compression, since flatheads are non interference, and dont work with my compression checker. it had full power, and started first pull before this happened. ive tried everything, except for a ball check valve, in the fuel pickup, the manual says to check. ive got spark all the time, not some intermitten thing also. i dont think it jumped timing/sheared the key, because it cant physicaly stall, like if you hit stuff, with a mower. help