Merc 7.4 MPI Injector Noise
 

I have a 7.4 MPI engine and I noticed a noise I haven't heard before.
When I turn the key on, along with the normal beeps from the dash
panel I notice a electric fuel pump type noise which lasts 2 or 3
seconds and eminates from the injector area. The unit runs fine but I
don't recall hearing this noise in the 5 years I've had this boat. Is
this something I should be concerned about? As I noted, maybe I just
dind't notice this before. Any comments would be appreciated.

Merc 7.4 MPI Injector Noise
 

It is normal operation for the high pressure fuel pump to pressurize the
injection feul rails before cranking the motor. The 2-3 seconds of the fuel
pump running sounds completely normal to me. Perhaps now that the system is
older the fuel rails are not holding the pressure from the last shut off to
the next start and were before, could be cause by the injectors are leaking
down the pressure a little. Or the fuel pump could be getting noisier with
age and you just didnt hear it before.

Paul


"Old Willie" wrote in message
om...
I have a 7.4 MPI engine and I noticed a noise I haven't heard before.
When I turn the key on, along with the normal beeps from the dash
panel I notice a electric fuel pump type noise which lasts 2 or 3
seconds and eminates from the injector area. The unit runs fine but I
don't recall hearing this noise in the 5 years I've had this boat. Is
this something I should be concerned about? As I noted, maybe I just
dind't notice this before. Any comments would be appreciated.