Electric pump fuel flow?

Was just running some fuel through the system on the ground for the first time using the electric pump, out to a gallon jug from the fuel servo output. Was surprised at the low fuel flow coming out, didn't seem like enough to run the engine at full power. Was not a strong flow like I would think. Engine started and ran fine, pressures okay. Throttle and mixture full open. Is this correct or do I have a restriction somewhere to go hunt down?

Thanks,
Dwight

Need more info

How long did it take to run out a gallon? What engine are you running? What is the manufacturer rated fuel flow at 100% power? 15 gph = four minutes for a gallon. 20 gph = 3 minutes for a gallon.

Without that info, I guess there is only one careless answer: No problem it runs. What the heck, go for it.

Numbers?

Quick calc suggests that .5 GPM would do the trick, what are you getting?

I'm thinking that aprox 25 GPH will run it at full power... Rounding up is 30GPH Or .5 GHM

Test before servo!

Couple of things.
The IO-540 demands 26.5 Gallons at full power.
Your fuel flow test needs to be run from the hose before the injection servo.
This is a fuel supply test where you can check the actual output of you electric fuel pump. An AFP pump produces about 56 gallons per hour, plenty for your 540.

Mine flowed 42 gph

and that is after going through my red cube in the tunnel. Yes, remove fuel servo "in" connection and the run a hose from there into your container. This was also the way I transfered fuel fom one tank to the other for grt ff calibration. I also get about 26 gph on takeoff. Keep your boost pump flow number for future reference, as it will tell you if your finger screens, filter or ff transducer are restricting fuel flow.

Will try that

Didn't try for the full gallon, it was taking too long. Will try it prior to the servo. Agree it should be more like 25 gph or more.

Dwight

Just a question here. Shouldn't the outflow be restricted so as to give minimum fuel pressure (14psi, I believe, for a D4A5)? Then you are measuring the flow at the operating pressure.

The fuel servo will only allow about 5-7 gph without sensing air flow. That is with mix full rich/throttle full open. So you would have had approx 1 gal after 10 min. This is basically the flow you get during priming. Approx 1 tsp or 5cc per cylinder during typical 5 sec priming.

I installed 15' of 3/8" fuel hose from auto parts store which created a little restriction. If one had a helper then just kink the rubber hose slightly or close a temporary valve until fp indication goes to 14 psi. I did not have a helper and figured if I was getting 42 gph then I should not have any problem. I guess one would find out for sure if mechanical pump fails on takeoff. Even then I should have enough flow to get me back for a landing. This plane will fly with fine with < 10 gph full rich.