Vane pump (Groco SPO) pump not pumping

[mdstrum]

I have two Vane Groco Diesel fuel transfer pumps. One is moving fuel well from tank A to B. The second one is not. The pumps are little over a year old and only been use a few times to move 100 gallon each time.

A good friend suggested putting an oz of motor oil or so in the pump head to help get better suction...I asked Groco and said sure that might help get it flowing.

Anyone have this issue and possible solutions as it seems when the pump sits for a few months unused this happens. And why would one work fine and other (mirror image setups on on the port and strb have issue and the other not?

 

[kapnd]

Are the pertinent valves open?
Is there power to the pump?
Is there fuel at the intake?
Is the outlet line obstructed?
Information needed to give any assistance, my crystal ball is out of order!

 

[HopCar]

The vane pumps are pretty simple, but the vanes need to be free to move in the Rotor. The first thing I’d do is take the front cover off and clean the vanes and Rotor. If the pump isn’t used often, it might have gotten some residue that is keeping the vanes from sliding freely.

 

[mdstrum]

Thanks, all values are open, pump has power and runs. Line is clear

good call I check the vanes for movement and no damages have only used the pump 2 times this year, last time was 3-4 months ago. What is odd, is the 2nd pump for the other tank is running fine. (it also sat for 3-4 months) but it is boat so it it can go wrong it will I guess.

 

[HopCar]

The other thing that can fail is the shaft hole in the Rotor can get rounded out and allow the shaft to spin without turning the Rotor. The Rotor might look ok with the cover off, it might even spin, but when the cover is on and a load put on it, the Rotor may slip. Pull the Rotor and examin the hole for wear.

 

[mdstrum]

Just sharing back, it turns out the issue was the tank vent port through the hull of boat, I noticed very little air coming out, so pulled the hose and like mage the pump worked way better, put in the new vent and all is happy. Thanks everyone.

 

[kapnd]

Good job locating your problem!
Vents are often overlooked when dealing with fuel flow issues, but are a very important factor.