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fuel pump testing

Hook up a pressure gauge (preferably glycerin dampened), never below 4 PSI at WOT at pump out. If hooking on the most 'far away' carb on a V6/8, min 1PSI at carb inlet.
The pressure will pulse with the pump, stated pressure is min.
 
VRO Pump
I checked my Fuel Pump pressure (part of VRO) not a separate fuel pump, and got 4 psi at idle about 1200 RPM in neutral. I have 2 carbs and removed third hose from the plastic manifold that exist the top of the VRO, the third hose goes to the primer solenoid to inject gas when you choke the engine, the other two hoses go to carb one and two. Put your gauge on the manifold port (primer solenoid hose removed port) and you can read the pressure right out of the VRO and going to both carbs while it is running. Book spec is 3 PSI minimum at 800 RPM in gear! Mine was 4 PSI in neutral 1200 RPM. Also if you change hoses to both carbs with these new yellow or clear hoses you can see the gas flow to both carbs and check to see if there are any air bubbles in the lines going to the carbs. I had leaks in both the fuel and oil lines (bad clamps = loose = missing tie wraps). Remember the other side of the VRO is vacuum (tank side), sucks air = bubbles with no visible leaks. I got the yellow hose at NAPA. The black tie wraps are special for gas, do not use electrical tie wraps.

This is an excellent link to a 6 page article on VRO, everything you wanted to know plus history, tests myths, alarms, upgrades.
Caution you know everything about VRO’s = PHD
http://continuouswave.com/whaler/reference/VRO.html
Portions Copyright © 2005 by James W. Hebert. Unauthorized reproduction prohibited!
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