I just finished a D950 rebuild and tried running for the first time. It ran but ran at what i consider max speed or overspeed. I turned the key to the off position and it continued running. The fuel shutoff solenoid went to the stop position but the engine did not stop. i had to turn the fuel off at the filter and after about 30 seconds it finally quit. During this time the throttle had no effect on the speed. It also was pouring black smoke out of the exhaust which tells me its getting way too much fuel. I pulled the pump apart and everything seems to be in order so far as i can tell. I reinstalled and the same has happened. I noticed the start spring had broke ad was rebent to fit putting additional tension on the spring. I have one on order but find it hard to believe this is the problem. When i crank the motor and manually hold the pumps fuel rail in the stopped position it still pumps fuel. should'nt this stop pumping fuel in the off position? What else should i check for regadring the governor operating correctly? The grass is growing and im out a mower! Thanks for the help in advance.