sounds like you have a bad wire somewhere. my saff had exactly the same problems as yours (eractic boost/sometimes wouldn't prime). check there is 12v going to the amal valve(mine only had 0.8v) run a wire from the -side of your coil to the live wire on the amal valve to fix this. rewiring the fuel pump is easy, i used the old amplifier wiring kit that was in my car when i got it and just ran a earth wire to a switchand i've never had any problems since