I have 9+, only thing I've had go bad with the pump is it is set too high stock and if the seal leaks you have to drain the carb if it you don't run it for a while. Never had one "fail". Still have my first QT50 running the stock pump with a YT60cc jug and head, MLM exhaust. Still running and pump is still a bit too high. I got it in 1993 btw.