Tractor Repair: fuel injection, electric fuel pump, david brown

Question
I have a 1970 david brown 990 the injection pump is geting air and the tractor only runs for about 5 min after it is primed i think it is the lift pump would there be a problem with just puting an electric pump on it

Answer
You can try the electric fuel pump but it is not necessary. Change the transfer pump and check the supply  line for bad lines and something clogging the tank inlet line. If all else fails put a clear line on the return to the tank as see if there are bubbles. If there is then you still have a suction problem