I have 38 Wellcraft with 2 525 SC in it..would like to know if any body knows what they require for fuel delivery? How much GPH on the mechanical pump, and do they need an electric backup pumps as well? Somebody has changed everything on this boat and want to put it back to stock..But i dont want to starve these beasts with fuel..

The use the same Merc mechanical fuel pump as the carbed HP500. Not sure what GPH they are rated at.
I upgraded the 525SC in my Pantera with a Crane 731 roller cam and was running 8# of boost and the stock mechanical fuel pump was plenty adequate.

So an electric pump as a back up is not needed??

No secondary electric fuel pump is needed

thanks..

Mercruiser spec on this back in the day was 3 to 7 psi at 1800 rpms. IMO fuel pressure at 3 psi is too low but that was Mercruiser OEM spec for this app. They never had a volume test of GPM or GPH listed for a diagnostic test.