mercruiser 5.0 mpi fuel pump trouble

[tuscan]

i just had my mercruiser 5.0 mpi fully serviced, which included a new fuel filter
when all was done, the fuel pump wont come on when you turn the key
normally once you turn the key you can hear the pump priming for about 5 secs but now nothing happens, engine cranks but fuel pump not pumping
has anyone any knowledge of this problem ??
looking through the forums someone suggested it may be the oil pressure switch, which disingages the fuel pump
cant see any obvious loose wires etc
the guy that serviced it says it may be the pump but it worked perfectly before he went at it ???????
engine has only 300 hrs and is 2006
would greatly appreciate ANY info
thanks for reading

 

[gery w]

had this problem on my 5.7 and it was the oil pressure switch take the two wires off the switch and short them together then turn on the ignition switch and the pump should run the switches are a common problem.