fuel presure 2,5 merc 260

[stevo18]

I have a problem with my fuel system, it only reads 35psi when the motor is not turning and when I start it up it goes down to 31psi when I am suppose to have 39psi. Over this winter I had my injectors flowed and cleaned by brucato and I changed the fuel pressure gauge for a new one that I checked with a gauge balancing tool that I had at work so its supposed to have the exact reading. I also changed the fuel filter and flushed all the lines before putting everything back together.

so I hade another used fuel pump laying around in my shop and decided to try that one to see if that was my problem and still gives me the same exact numbers 35psi when motor is not turning and 31psi when it's on. So I was thinking of changing the regulator on top since I pulled up the little vacuum hose hand there was a lot of gunk it was almost blocked.

so what do guys think am I on the right track or???
thanks in advance for any info
steve

[rev.ronnie]

Gunk and regulators don't mix. I would think that to be a 99% chance at being your problem. They are referenced from manifold vac.

[stevo18]

ok thats what I taught. I will order one this morning but I was thinking of putting an adjustable reg if it's not to expensive.