I had an interesting talk with Greg at Duke's the other day.  I was inquiring about positioning the fuel pump to avoid the occasional "burping" that has been reported at flight levels. 

 

He stated that the fuel pump could be positioned horizontally if desired.  However, he cautioned that the drain needs to be pointing downward.  The concern is that failure of the internal seal can cause fuel to drain through the electrical if the drain is mounted on top.

 

I have positioned my fuel pump on the copilot's side at a 45 degree angle to the floor of the fuselage.  Positioning is the same as Carls, inboard of the copilot's exhaust tunnel and as close to the firewall as possible, except the drain points downward.

 

I can forward photos if anyone is interested.

 

Craig Gainza

IV-P