was it running like faster than you ever had it on wide open with the throttel??? was it blowing any smoke?? Might want to check the oil and see if its higher than full,, if so you most likely have a injector stuck open and fuel is leaking past the piston and into the oill this could dilute the oil enough to where the oil could be fuel that is causing it to run wide open a very very dangerous situation. could eaisly turn into a runaway motor and destroy its self, I would also double check your linkage at the pump itself ... but if you start it again and it takes off you need to shut it down like you did so be prepared for it.
