Alright guys I'm in need of some advice. Just recently I bought an old Briggs 5hp engine, which won't run well. It will start, idle, and run for maybe 10 minutes, and then shuts off. It is extremely hard to restart too. It also will die whenever move the throttle more than half way. So far I've cleaned the tank, and carb, replaced the diaphragm , fuel pickup tube , mixture needle , air filter , changed the spark plug, cleaned the carbon off the valves, and checked the flywheel key way. After all this its still running like junk, what else is left for me to do ?