mjb

I am looking for an engine fuel plumbing diagram for a stock hp525efi. My mercruiser manuals have the 502mpi but are not current enough for the 525efi. Can anyone post one or provide a link ???
Thanks-

Dave_N

Hope this helps.

Dave

mjb

....and Dave N comes to the rescue AGAIN!! Thanks for the quick reply. I am a little surprised to see that the 525 uses the same layout as my older 502mpi. I would have thought that they would have relocated the regulator after the fuel rails by now. My pressure gauge on my fuel rail bounces around so much with my modified 502's that I am getting ready to re plumb my fuel system so the rail sees full fuel flow with the regulator after the rail. Do you think that will solve the needle bounce problem? Do you think it will increase power or am I wasting my time?
Thanks-

Dave_N

The flow diagram does not show the pressure dampner. You should be able to rig up something similar to this setup on your motors.

Dave

mjb

Actually, my current set up('97 cool fuel) already has a dampner on the front of the rail but my needle still bounces around like crazy. My engine mod's include a larger cam and increased fuel pressure to 48psi. I have never really liked the mercruiser "deadhead" regulator arrangement but it seemed to work ok with stock fuel demands. I think that the stock set up coupled with my increased fuel demand and pressure and bank injection are causing the pressure flucuations in the rail. By moving my regulator after the rail and eliminating the dead head configuration, I hope to smooth out the pressure spikes. I would be interested in any opinions from those who have experience with this.
Thanks-

gsmith9898

how often do you change the inline filter in front of the rails?