Adjusting PMO Fuel Regulator

[timtimm]

According to pmocarb.com the fuel regulator is adjustable. How do you adjust it?

Due to the differences in output from the mfi fuel pump to my new pierburg, it seems
as thought the regulator now might be allowing too little fuel to the carbs. The gauge
would bounce around with the original mfi pump, and the new pierburg pump won't move
the needle off of 0...Tim

[moneymanager]

On mine you just turn the little knob on the regulator. I wonder if your's is from PMO?

[timtimm]

I'll go look now, where is the knob? Thanks for the info...Tim
ps. My PMO kit is circa 1989-90, if that makes a difference

[moneymanager]

Again, on mine, right in front of you as you look at it. But mine dates from 2007 so things might have changed.

[timtimm]

This is what I got...

[Paul W]

That's not a regulator, just an outlet. I've the same fitting on my car.

[James Brown]

timtimm, couple of things, try to use fuel injection clamps, they won't damage the hoses as the worm clamps your using now. And, the pressure gage should be a fuel pressure gage, the fuel might eat through a gage designed for air pressure. Just some safety tips.

[timtimm]

Million dollar question! How did my carbs handle all of the pressure from the mfi
fuel pump without any type of pressure regulator? Everything that I have read,
tells me that the unregulated pressure would damage the floats. The car ran
great, until I let it sit up for 5 years...

[James Brown]

that is a good question, try looking around for a regulator, might be a in-line type downstream from the pump.

[VFR750]

More info please. Is your new pump designed to run at high pressure with recirculation back to the tank?

The typical pmo regulator is designed with a full recirculation fuel system. It uses a metering valve to block a little bit of the flow, resulting in some pressure to the carbs. Screw the plunger in to raise the blockage and pressure to your carbs.

If the pump does not flow as much as before and/or the pressure rise is not as much as before, then the existing position of the valve may be too far out to restrict the flow as to backpressure the pump. Agian, turn the screw/valve inward (clockwise from the top) to increase backpressure to the carbs.

[BK911]

Originally Posted by timtimm

Million dollar question! How did my carbs handle all of the pressure from the mfi
fuel pump without any type of pressure regulator? Everything that I have read,
tells me that the unregulated pressure would damage the floats. The car ran
great, until I let it sit up for 5 years...

A high pressure fuel pump has the ability to pump to high pressure. But without system restrictions the pump will not create the high pressure. For example, my CIS fuel pump is capable of pumping around 85? psi? But in a complete open system without restrictions, it only pumps about 3 psi. I had to use the PMO regulator to restrict the system to increase the system pressure to 4.5 psi.

[jmcn3rd]

Maybe pickup one of these, works nice.

[RWebb]

yes get that; throw away the old hose (damaged) and the clamps; use new fuel hose rated for EtOH and ABA or similar clamps

inspect all other hoses!

[timtimm]

I picked up one of the old style regulators from PMO that
that looks like a faucet valve. I installed it and closed the
valve, and immediately got 3lbs of pressure.

I can now commence the tune up, knowing that I am
getting the correct amount of pressure to the carbs.

Thanks for all of the advice. I will be replacing the old
hose as well as the old style worm clamps....Tim

[RWebb]

faucet valve?

[timtimm]

That sure is it, minus the red valve....