Just rebuilt the c223 in my '84 p'up after the head gasket blew. Now it won't run unless the pedal's on the floor, and then only about 1000 rpm. If I hold it wide open it will start and run, but as soon as I release the pedal even a little bit, it immediately dies. Also the manual pump on top of the fuel filter just pumps bubbles all the time, no matter how much fuel I pump through it. Any ideas? I think its in that hand pump, maybe a bad seal. The fuel filter's brand new, with a new o-ring on the sensor at the bottom, I cant find any fuel leaks there. I know it will run ok, if I fill the filter with fuel, it runs fine on that until it needs to bring fuel from the tank, then it can't pull enough to keep going. I've tried blowing out the fuel lines, but that didn't make any difference.