Ok thanks to the help of everyone’s discussion on this page I have the performance issues on my 2004 Powerquest 320sc narrowed down the the pressure regulator on my cool fuel 2 unit. Pressures are running low. If I pull the vacuum line from the cool fuel regulator my pressure pops right up to 44-46 psi. 43 being the magic number. If I plugged the vacuum line back in they drop to 36psi. Boat runs great with 44-46 psi and horrible at 36psi. Regulator diaphragm holds vacuum and opens quickly with any vacuum. Seems like the spring in it must be broken. Running with load on the engine pressures never make it anywhere close to 40 psi with the reg hooked up to manifold vacuum. Clearly and issue with the reg. Pump will pump past 52 psi with both regulators off line.

so question is, it seems raylar uses an adjustable rail pressure regulator to boost pressure above 43 psi. They must be eliminating the cool fuel regulator to do that.

What is the function of the dual regulators? Seem like I can just eliminate the cool fuel Regs and run with the rail regulator doing all of the regulating? Am I missing any key function of the dual regulators other than redundancy?

Thanks in advance for any insight.

You may want to start with an inspection of the fuel pressure regulator plus the little screen under the regulator down at the fuel lower 'port side fuel pump area as the one that appears to be an fuel regulator up-top of the engine inline with the fuel rail is actually a fuel rail pulse damper for the rail & injector system...It doesn't regulate the fuel pressure system per se.

The following is a description and or a guide should you need to open it up for an inspection in case there happens to be debris inside the fuel rail & injector systems...A new clip like mentioned in the following under warranty was only needed for engines right around the 2006 era.
http://ww2.justanswer.com/uploads/ke...5804_EN_09.pdf

those pumps seem to get lazy with age start with a fresh one first