Acceptable Fuel Pressure?

[CRAZEDpilot]

So I pulled the power off to about idle and was descending...... noticed that the fuel pressure REALLLLY drips back,
to about 1.5psi on the old fuel pressure gauge.

Is that acceptable to keep her idling ok ? Anyone else know their idle IRM fuel pressure readings? Thanks.

-Brendan

[HeavyLoad]

I'm assuming this is for a carbureted lycoming 180? Yes that does seem pretty low to me. Is this a analog gauge you are using? Do you have a way to disconnect and check the gauge?

[andy]

Did you try the electric fuel pump to see if the pressure went up? If I remember correctly, mine goes up from around 3 psi to 6 psi when I use the electric fuel pump.

[VA Maule]

Carburetor really doesn't need much pressure at all as long as there's enough flow to fill the bowl as the flote allows it in. In fact as comfortable and reassuring as 4,5 or 6 PSI reading is it's not necessary for a carbureted engine and too much pressure can overpower the ability of the flote to maintain the correct fuel level and create an extremely over rich condition.

Now fuel injection does require a significant pressure to work but that's not the conversation here.

[bushcub]

According to the MXT7-180 Flight Manual, the normal fuel pressure range is 0.5 to 8 psi.. I get 0.5 just sitting the hangar due to the head pressure from the height of the tanks above the engine.
Mike

[CRAZEDpilot]

Thanks for all the replies, in cruise it's Like 3psi, boost pump takes it to 6 even on the ground with engine off.......
so i'm guessing 1psi or so when i pull all the power rout isn't that surprising.

Thanks all!
-Brendan

[andy]

I checked mine during run-up yesterday. It was about 4 psi without the electric fuel pump and 6 psi with it.

[CRAZEDpilot]

And when you say 'during runup' you mean at 1700RPM or 2000RPM or something?

[andy]

2000 RPM